well let me tell you, i play exclusively diety and it involves a lot of luck. try to go for a lot of luxuries and strategic resources, because it becomes the best trading leverage tool for humans. also, try to stay out of wars early on, except if one civ is getting hammered by another AI(s) and you want to jump in and join to grab some land. early on, its expansion, expansion, expansion, and building some culture. set research at 20% to start, then move down to 10% so that you are still researching, making it cheaper to buy techs that you are researching. later on, move it to 0% and use 1 scientist in any city to keep research going.
you have to face the fact that most of the diety games will end up being too hard to make a comback when you are too behind. me, i will win maybe one out of six or seven games that i play past ancient age. it seems to me it makes a world of difference having a super-food tile at start so that you can somewhat contain AI's rapid expansion. try building extra warriors to block AI settlers back and forth between few tiles, as i have just started doing this and it helps a little getting some cities that AI would have gotten otherwise.
give up on most wonders early on, as it will be almost impossible to outbuild AI in wonders without leaders. and try to get at least one leader, by using your elites at the right time every war. try to go to war with other civs aiding you, if you can. dont sign MPP too much because it will get you into too many wars.
this said, i think winning diety comes down to a handful of critical moves and a whole lot of luck. my last game, i was doomed as egypt, surrounded by 4 AIs in the same small continent. however, i took the chance and went after the smallest AI civ in Greece in ancient age, even though they have the dreaded hoplites. with mass war chariots/horsies, i managed to get a leader out of the war, allowing me to rush the great library that saved the whole game. from there on, i was right back in it and it allowed me to build units on par with other AIs, allowing me to take over the rest of the continent eventually.
if you make it to industrial age and ur still in it, then you have a good chance. i just started using spy/embassies to steal techs and i like it. in the modern age, i'd rather steal techs even if i have to pay a lot using "carefully" because i want to deny the AI the money they would get if i traded for it.
so basically, in my opinion, these factors are the most important in winning diety.
1. starting with a super-food tile.
2. having enough land on ur continent to have a decent # of cities.
3. rapid expansion to keep up with AI.
4. getting leaders to rush crucial wonders
5. getting good # of different luxuries and resources to trade with AI for techs.
6. extorting techs out of badly beaten AIs.
7. getting early contacts with as many civs as possible to trade techs, resources/luxuries.
8. staying out of wars until you are ready. sneak attacks by AI can ruin your game easily, so try to stack up on units and guard your borders. also have a lot of units even if u dont need them at the time, as AI will constantly threaten you if you have weak military