* This post is based on deity level play, but most of them can be applied for other difficulty levels also.
* Some of them could sound like "exploits". I would not argue what is okay and what is not - a reader may decide. All I can say is these tactics are not using bugs. I sometimes self-ban some of these to make my games more interesting and challenging.
I. Worker(s) steal
As AIs start with 2 settlers at the deity level, it is actually easier to steal worker(s) from other civs, compared to the immortal level. While I almost always steal given a chance, usually it is not easy to get multiple workers and in rare cases, it's difficult to get a single worker from other civs. Unless you steal 3+ workers, it is usually better to get workers from CS (City State). By t50 (standard), for a usual pangea game, I get one worker from other civ and 2-3 from a CS.
There are other threads about how to steal multiple workers from a CS, so I keep it short. In short, you need to wait a lux/resource tile that the first CS worker was trying to improve, steal the first one, and wait 2 tiles away from that tile and the border.
Make sure that your unit is not on the hill (it is visible if it is on the hill). In many cases, you need to let one of your scout to wait there so that you can move over hill/forest to catch 2nd, 3rd, and so on. Moreover, you should be able to expect how the CS border would expand so that you make sure that you can wait 2 tiles away after border expansions, if possible. You can find lots of examples when you read deity challenge thread/gotm.
II. XP farming and getting (free) Great General
While there are not that many early wars in BNW, you still need some archers to defend against barbs, do barb quests, and defend against other civs if necessary. If you have units that are idle, send them to the CS that you have stolen workers, and stack XPs. Remember that attacking a city gives 3XP, while attacking units gives 2XP. Hence, you can stack XPs much faster and you can get logistics/range promotion much earlier than usual. Moreover, you can get great general this way.
If you are going to do some war, these certainly helps, and even if you are not going to, it will give you a free GG to get additional land if needed and help to prevent wars by having more veterans.
One good example is a recent deity challenge:
http://forums.civfanatics.com/showthread.php?t=528421
Take a look at my writeup and you can see that with Zulu UA, you can get logistics and range promotion archer (yes, not even CB...) only with CS attacking. When you upgrade this unit to Xbow, it just kills everything.
III. CS "shield"
This tactic is not applicable (not required) in most cases, but if you have a Zulu/Aztec/Mongols/Huns/Assyrians as your neighbor, this could be helpful. You know that these aggressive guys will attack someone early. If they don't attack someone else and you cannot bribe them to DoW others, they are going to attack you and you are in trouble - even if you can defend, it will waste units and turns that you need to build science/gold/culture buildings.
In that case, bribe them to attack CS, and cover the tiles with your units so that AI cannot "last hit" to capture. City state will kill AI units one by one, and you can basically reduce his troops. One nice example of this is Deity Challenge 33: France Pangea culture game. http://forums.civfanatics.com/showthread.php?t=508392&highlight=deity+challenge&page=2
IV. "Free" ally CS, especially for domination games
The irony is that you steal say 3-4 workers from this CS, use it as a boot-camp to stack XPs, and you can ally this CS for free later!
When you DoW (or CS does), your relationship goes to -60, but it goes to zero for each turn as usual - you just cannot observe it and it shows -60 during the war. So for example, if you make peace after 60 turns, it will show you zero influence.
During the war, workers need to build roads and scout. In many cases, you even have to use workers to lure AI units out (let them capture, you kill it and get it back). By using workers as your 'front units', you can prevent AI attacks and cut their units one by one with your range units. Moreover, when they capture and you re-capture it, in many cases that worker was from the CS and it asks you to keep or return. Usually at this stage, you have more than enough workers (you are capturing other civs' workers) so just return them for free influence (45 iirc). For most of my domination games, I get 100+ free influence from just returning workers to their hometown after slavery.
V. Bonus: Venice strategy
This one works well for early games. As AIs techs a lot faster than a player at the beginning, you can see that city states got CB/swordsman/pikeman/knights where you are like 15 or more turns from the necessary techs.
If you want to take some caps, look for city states nearby. Military states are better as they tend to have more units and upgrade existing units asap. city states with iron/horse are better as they can upgrade warrior/swordsman/horseman. I will explain the strategy in terms of CB rush, for simplicity.
Build some archers. When you find a target and proper CS nearby, gift your archers to that CS - and send your UU (protect with say 2 archers) to that CS. Gifting takes 3 turns so you can send units fairly easily. you are moving with only 2-3 units so AIs won't ask you whether you are going to attack them or not.
CS will upgrade archers to CBs when they receive archers. They tend to have spears/swordsman/horseman too. You don't have to pay for upgrade costs, maintenance costs, moving times, etc. Just get that CS with your merchant! all of a sudden, you have lots or army near your target - taking it would be a piece of cake. Moreover, this one can be done several times.
* Some of them could sound like "exploits". I would not argue what is okay and what is not - a reader may decide. All I can say is these tactics are not using bugs. I sometimes self-ban some of these to make my games more interesting and challenging.
I. Worker(s) steal
As AIs start with 2 settlers at the deity level, it is actually easier to steal worker(s) from other civs, compared to the immortal level. While I almost always steal given a chance, usually it is not easy to get multiple workers and in rare cases, it's difficult to get a single worker from other civs. Unless you steal 3+ workers, it is usually better to get workers from CS (City State). By t50 (standard), for a usual pangea game, I get one worker from other civ and 2-3 from a CS.
There are other threads about how to steal multiple workers from a CS, so I keep it short. In short, you need to wait a lux/resource tile that the first CS worker was trying to improve, steal the first one, and wait 2 tiles away from that tile and the border.
Make sure that your unit is not on the hill (it is visible if it is on the hill). In many cases, you need to let one of your scout to wait there so that you can move over hill/forest to catch 2nd, 3rd, and so on. Moreover, you should be able to expect how the CS border would expand so that you make sure that you can wait 2 tiles away after border expansions, if possible. You can find lots of examples when you read deity challenge thread/gotm.
II. XP farming and getting (free) Great General
While there are not that many early wars in BNW, you still need some archers to defend against barbs, do barb quests, and defend against other civs if necessary. If you have units that are idle, send them to the CS that you have stolen workers, and stack XPs. Remember that attacking a city gives 3XP, while attacking units gives 2XP. Hence, you can stack XPs much faster and you can get logistics/range promotion much earlier than usual. Moreover, you can get great general this way.
If you are going to do some war, these certainly helps, and even if you are not going to, it will give you a free GG to get additional land if needed and help to prevent wars by having more veterans.
One good example is a recent deity challenge:
http://forums.civfanatics.com/showthread.php?t=528421
Take a look at my writeup and you can see that with Zulu UA, you can get logistics and range promotion archer (yes, not even CB...) only with CS attacking. When you upgrade this unit to Xbow, it just kills everything.
III. CS "shield"
This tactic is not applicable (not required) in most cases, but if you have a Zulu/Aztec/Mongols/Huns/Assyrians as your neighbor, this could be helpful. You know that these aggressive guys will attack someone early. If they don't attack someone else and you cannot bribe them to DoW others, they are going to attack you and you are in trouble - even if you can defend, it will waste units and turns that you need to build science/gold/culture buildings.
In that case, bribe them to attack CS, and cover the tiles with your units so that AI cannot "last hit" to capture. City state will kill AI units one by one, and you can basically reduce his troops. One nice example of this is Deity Challenge 33: France Pangea culture game. http://forums.civfanatics.com/showthread.php?t=508392&highlight=deity+challenge&page=2
IV. "Free" ally CS, especially for domination games
The irony is that you steal say 3-4 workers from this CS, use it as a boot-camp to stack XPs, and you can ally this CS for free later!
When you DoW (or CS does), your relationship goes to -60, but it goes to zero for each turn as usual - you just cannot observe it and it shows -60 during the war. So for example, if you make peace after 60 turns, it will show you zero influence.
During the war, workers need to build roads and scout. In many cases, you even have to use workers to lure AI units out (let them capture, you kill it and get it back). By using workers as your 'front units', you can prevent AI attacks and cut their units one by one with your range units. Moreover, when they capture and you re-capture it, in many cases that worker was from the CS and it asks you to keep or return. Usually at this stage, you have more than enough workers (you are capturing other civs' workers) so just return them for free influence (45 iirc). For most of my domination games, I get 100+ free influence from just returning workers to their hometown after slavery.
V. Bonus: Venice strategy
This one works well for early games. As AIs techs a lot faster than a player at the beginning, you can see that city states got CB/swordsman/pikeman/knights where you are like 15 or more turns from the necessary techs.
If you want to take some caps, look for city states nearby. Military states are better as they tend to have more units and upgrade existing units asap. city states with iron/horse are better as they can upgrade warrior/swordsman/horseman. I will explain the strategy in terms of CB rush, for simplicity.
Build some archers. When you find a target and proper CS nearby, gift your archers to that CS - and send your UU (protect with say 2 archers) to that CS. Gifting takes 3 turns so you can send units fairly easily. you are moving with only 2-3 units so AIs won't ask you whether you are going to attack them or not.
CS will upgrade archers to CBs when they receive archers. They tend to have spears/swordsman/horseman too. You don't have to pay for upgrade costs, maintenance costs, moving times, etc. Just get that CS with your merchant! all of a sudden, you have lots or army near your target - taking it would be a piece of cake. Moreover, this one can be done several times.
(perhaps a short video exemplification ?) ..
And he's an admin who play very often too. 
