Like I said, the better you are, the less the need for save&reload. I am a casual player, I don't play civ all day every day. I don't care if you don't like save&reload. If you preffer to play on a tiny map with all options tweaked only to get a win on deity, good for you. I don't. I only play on HUGE maps and considering the kind of advantages the AI has on deity, a few reloads here and there will go unnoticed. The thing is that you will never learn if you restart 100 times.
Save and load, and in time you will get better at anticipating enemy's moves. Eventually, you won't need to save anymore. This is a thread for strategy and tips for deity. Let's keep it like that.
I attached some saves. Unfortunatelly, my later saves are too big to attach so I cannot give you a sample of my tech race. If anyone knows how to upload 1MB files, please let me know.
VirusMonster, here are some of my thoughts on the strategy for deity. Feel free to comment on them
Most of them have been pointed out already, but I think they deserve more attention in a deity game.
I think researching Alphabet should be one of the initial priorities. Most of the time you will be the first one to get it. Even if you ignore many of the other cheaper techs, once you get Alphabet you can trade it for every tech out there and much more.
In a deity game the AI has HUGE amounts of gold. You can use that on your advantage. Trade resources for gold and also check regulary if the AI has more gold available for trade. If so, cancel your previous trade agreement and make a new one for more $. Exchange good techs for lesser techs+gold, and so on. In a 18 civs game, the AI will be your cash cow. In this game, I managed to stay at 100% research most of the time after getting Code of laws and Curency. I was loosing 100 gold per turn, but the AI is rich and it doesn't care about money

I even managed to lead in research, I got Music, Liberalism, Economics and Physics first. I also managed to build The Taj Mahal and Great Library thanks to my 5 capitals

Since I had 100% research, I didn't build any banks or markets until late in the game. In a way, libraries were "generating" gold for me.
The trick I like to use before I attack a nation, is to bribe someone else to go to war with them first. Someone who is on the other side of the targeted nation. I wait a few turns, around 6, and then I attack. This way the bulk of their forces will be on the other side of the country, fighting the other enemy. This leaves their cities poorly defended.
Check the power graph regulary. If you notice that one civ's curve is going straight up, that means they are building tons of troops and getting ready for war. Consider their strength as opposed to yours, how much they like you, if they are neightbors with you, etc. Chances are that they will go to war with you, so be ready for a tough defense. In this particular game, Washington declared war on me. I knew he would, so I waited behind my city defenses with 50+ infantry. After 3 turns I only had 30 left, but most of their army was gone.
Ah, the most important one: gunpowder units with City Raider III are OWNAGE. It doesn't matter what level of difficulty you are playing on, a stack of riflemen with City Raider is unstoppable. Ofcourse, City Raider promotion cannot pe applied to gunpower units, so you need to upgrade those veteran quechuas, axemen and macemen. But they are worth the price. I don't know how to emphasize this enough. Those units will probably have +100% or more against cities. A few catapults to lower the defense even more and you'll take the city with minimal or no casualties.
You should also upgrade a unit after a promotion. For example, if you have a macemen with 23/26 exp, don't upgrade it imediatelly to riflemen. Kill a few weak units with it and then promote+upgrade. If he had 18/26 exp, then I would upgrade and forget the promotion.
Besides these, the usual: chop, cottage spam, diplomacy, quachuas rush, steal workers, etc.
All civ games are different so you need to addapt your strategies to the game. Everybody talks about luck in a game, but I think we should see it from a different perspective. Luck is the randomness in the game. From the way this game is built, there is a high probability that most games will have about the same difficulty, only that they will be TOTALLY different. This is the beauty of CIVILIZATION.