This game needs an engine with a learning capability, so it can figure YOU out! (I'd pay triple for a feature like that.)
First off, I don't play with cultural, diplomatic or space race victories turned on. In fact, I don't even like dominance. If I wanted peace, love and understanding I'd go back to doing drugs. (I lived through the '60s; I just don't remember a lot about it. Even my tour in Vietnam is still pretty much of a blood-red blur.) And besides, who wants to lose a two week old game on any given turn to some civ with a better namby-pamby cultural score than you, or a civ that's better at diplomatic sucking up, or one that can put an oversized Tonka truck on some godforsaken planet somewhere. NO, my friends, conquest is what this game is all about for me.
And secondly, I don't like the 2050 deadline; no sir, I don't like it at all. On a huge map it always comes just when things are really starting to get intense and interesting. So, I use hwinkel's TCG savGame editor to fix that little oversight:
http://forums.civfanatics.com/showthread.php?s=&threadid=15620
I typically play on a huge map with 2 less civs than are available. (A little more leg room.) It seems that I always choose to be the Greeks; don't know why really; just do. In the beginning I go after the civ that always seems to be hassling me from right next door. In doing this I gain small towns without having to settle them, and hopefully retain most of my warriors. After I've eliminated that civ, I try my best to remain peaceful during at least the first two eras, since a prolonged war during the early part of the game will leave you far behind the rest of the world. (i.e. I once fought just such a war with Egypt, and in the end, even though I won, I was still left defending my cities with pikemen while the rest of the civs were tooling around with battleships, etc.)
I Build lots'a workers!!! There is nothing that I know of to get your civ moving faster and insure you remain competitive better than workers.
I hardly ever give anyone ROP (especially not to superior civs); it's a sure-fire way to be overrun by a 'friendly' expansionist or militaristic neighbor whose calculations show that he's stronger than you are. And he'll blind-side you, no matter what treaties you share, if he needs your resources. (Although I don't get too freaked out about units passing through my territory on their way to a war somewhere else; only when they start massing around MY cities....)
I pay tribute to stronger civs, but log it in my little black book for later pay-back. Be careful, tribute paid too often can lead to an invasion by just such a power. DON'T BE A TOTAL WIMP! If I don't want to deal with it, I just close out of the diplomatic screen with the 'I'm finished' option.
I NEVER settle a war (when I'm winning) without getting techs as part of the settlement. NEVER! (Duh, unless, of course, they don't have any to offer.)
Modern armor, modern armor, modern armor . . . just can't say enough about it. If you wanna dink around with other units you do it at your own peril. If you're fighting on a huge global scale you need to do some serious butt-kicking (taking out two or three cities on a single turn). Armies with ONLY modern armor in them is the way to go. (Armies move with the slowest unit, so all of them need to be modern armor.) I build the Heroic Epic & military academy, then I can build army generals in that city just like any other unit. It also allows you to load 4 units into your armies instead of 3. I just love stacks of enemy infantry and marines. They die with such valor.
I hide my navy until I need it. It seems that other civs become 'cocky' with theirs when you're not showing any on the board. Hell, they cruise right up next to your port cities to bombard you without thinking twice, and then don't bother to retreat very far. I destroyed over twenty English ships (battleships, cruisers, etc.) on a single turn by 'surprising' them in just this manner.
Worried about my standing with other civs??? Not where my own best interests are concerned. I attack when I have to, I need to, or I want to.
I don't use ICBMs unless they do. And if they do, I'll use them more often than not to take out their vital strategic resources like, say, their only uranium deposit, or their only two sources of rubber. This sure puts a crimp in their military unit production, and it takes time to clean up the pollution (it seems that the AI is, in all honesty, not too swift about assigning large numbers of workers to ANY task) and then build a road to reinstate the resource . . . time I can use to my benefit.
The games I play are long (two or three weeks . . . well over 150 hours) but I like them that way. Conquering a huge map is a rush of lengthy proportions, and it's scary, frustrating and intense. I like scary, frustrating and intense.

ES