I think what you are dealing with is unclear build order.
You need to take full advantage of your early cities reproductive rate or shield production...
If a city has tons of food but takes forever to build stuff, you use it for a worker / settler factory...
If tons of shield output make it your military or great wonder factory.
getting a granary or a very good food supply early on is important and you'll realize that if you come out strong from the beginning and stay ahead of the competition, the military is rather easy to cover... It takes longer to populate and build new cities than it does to make your military... I suggest that either your starting, or second city have very fast population rate... You need to pump out settlers and workers fast or the enemy will just build cities all around you, forcing you to have no civilization.
I have found that having one city constantly producing settler or worker / wealth, and one for barracks / military early on helps you expand very fast... times that by two and you'll fill out your continent faster than other civs and they wont dare mess with you.
Dont settle for a pop increase every 10 turns, you need to cut that in half... fast. Your starting city should either be located near some food, or be close enough that your second city can start the civ factory. If you have 2 cities that can reproduce fast, yer in a good position. put one warrior or spearman in each new city as soon as you put them down and another while making another settler. two units per city = happy citizens who don't corrupt on you. That is, not to say that they never corrupt; just that they will corrupt less feeling safely guarded.
That being said, you don't need to use all spearmen from the start... I actually suggest mixing spearmen / warrior... your warrior will always be 1 gold a turn, where your spearmen line get rather expensive down the line.
Always build at least 1 of the latest military advance, even if its a catapult... enemy checks to see whether you are using at least 1 unit of the latest advance... "The enemy fears our swordsman sire" etc. This gets you better science and lux deals... the more the enemy fears you, the better they consider to you. polite / annoyed, etc.. This plays into their agressiveness as well, but it helps to have a leg up.
Wipe out militaristic nations first. They will always give you crappy deals on anything and are not impressed by your military, no matter how huge it is. Capture a few cities and sell them back to the militaristic nation to get all the research and gold you used to amass your army.. When you get back what you would have gained, start the steam roller and roll from city to city until the civ is wiped out.
Don't start a war unless you plan to finish it. Civs will never forgive you if you raze their city and they will always be pissed if you are living in a city they built. You can stop and sue for peace to get a leg up on techs and extra cities, but don't be fooled into thinking its over... Your reputation is toast if you start a war and don't genocide them off the map.
3 cities or so from extinction and you can usually sue their last extra cities from them, saving you the headache and lost research, as well as unhappy citizens. Then just say "I'm tired of your insulence, prepare for war!' and finish the job... This drops your score, not lasting the full 20 rounds of the agreement, but you get so much score for conquering 2-4 cities in one turn, that its worth it. Think about taking 2 or 3 turns to take 4 cities, and how much research you could have got done if you didn't have to pay your units to conquer those cities... 3 cities in one turn and extinction in the next turn = huge huge score and well done strat. When they plain give you a city you get the best defender that can be built from that city. (if they are connected to iron, you could get a pikeman, etc)
I dunno if you needed this help... but figure I'd pass it on, since I had a hard time learning this.
You need to take full advantage of your early cities reproductive rate or shield production...
If a city has tons of food but takes forever to build stuff, you use it for a worker / settler factory...
If tons of shield output make it your military or great wonder factory.
getting a granary or a very good food supply early on is important and you'll realize that if you come out strong from the beginning and stay ahead of the competition, the military is rather easy to cover... It takes longer to populate and build new cities than it does to make your military... I suggest that either your starting, or second city have very fast population rate... You need to pump out settlers and workers fast or the enemy will just build cities all around you, forcing you to have no civilization.
I have found that having one city constantly producing settler or worker / wealth, and one for barracks / military early on helps you expand very fast... times that by two and you'll fill out your continent faster than other civs and they wont dare mess with you.
Dont settle for a pop increase every 10 turns, you need to cut that in half... fast. Your starting city should either be located near some food, or be close enough that your second city can start the civ factory. If you have 2 cities that can reproduce fast, yer in a good position. put one warrior or spearman in each new city as soon as you put them down and another while making another settler. two units per city = happy citizens who don't corrupt on you. That is, not to say that they never corrupt; just that they will corrupt less feeling safely guarded.
That being said, you don't need to use all spearmen from the start... I actually suggest mixing spearmen / warrior... your warrior will always be 1 gold a turn, where your spearmen line get rather expensive down the line.
Always build at least 1 of the latest military advance, even if its a catapult... enemy checks to see whether you are using at least 1 unit of the latest advance... "The enemy fears our swordsman sire" etc. This gets you better science and lux deals... the more the enemy fears you, the better they consider to you. polite / annoyed, etc.. This plays into their agressiveness as well, but it helps to have a leg up.
Wipe out militaristic nations first. They will always give you crappy deals on anything and are not impressed by your military, no matter how huge it is. Capture a few cities and sell them back to the militaristic nation to get all the research and gold you used to amass your army.. When you get back what you would have gained, start the steam roller and roll from city to city until the civ is wiped out.
Don't start a war unless you plan to finish it. Civs will never forgive you if you raze their city and they will always be pissed if you are living in a city they built. You can stop and sue for peace to get a leg up on techs and extra cities, but don't be fooled into thinking its over... Your reputation is toast if you start a war and don't genocide them off the map.
3 cities or so from extinction and you can usually sue their last extra cities from them, saving you the headache and lost research, as well as unhappy citizens. Then just say "I'm tired of your insulence, prepare for war!' and finish the job... This drops your score, not lasting the full 20 rounds of the agreement, but you get so much score for conquering 2-4 cities in one turn, that its worth it. Think about taking 2 or 3 turns to take 4 cities, and how much research you could have got done if you didn't have to pay your units to conquer those cities... 3 cities in one turn and extinction in the next turn = huge huge score and well done strat. When they plain give you a city you get the best defender that can be built from that city. (if they are connected to iron, you could get a pikeman, etc)
I dunno if you needed this help... but figure I'd pass it on, since I had a hard time learning this.