i usally play both online and off with a small army because i go for culture and space victories which require pretty well developed cities...

i try to compensate by being a step ahead in army tech, but i dont think im doing all i can because ive never finished the tech tree and rarely get to modern armor and jet fighters...

I thought that these civics would be the best for high tech, but im sure some of u are better than i am:

Representation
Free Speech
Caste System
Mercentalism
Free Religion

Well, finishing the tech tree shouldn't be your priority anyway. If you go for conquest you should have the game pretty much won by the time you get composites anyway. :) You'll find that most players won't even reach those late techs, but win before that. It's just normal. The only time they're really useful is when you go for Space Race victory and you need most of them anyway.

As for the civics, well, it depends. :) For example, Mercantilism might mean smaller incomes, enough for you to have to reduce the science rate. So you'd probably need State Property more. Caste System? That late in the game it means a sure happiness penalty due to the fact that most of the other civs run Emancipation. But early on it really is a good way to maximize research. Only problem is, it competes with Slavery, which is the civic that in many people's opinions is the most useful one. Nothing like whipping to get your infrastructure/units fast.

So change civics to meet certain goals. Adapt. That's the biggest advantage we have on computers. So far... ;)

It may seem contrary to what you want to acchieve, but the best advice is probably to build yourself a bigger army and go kick your neighbours arse. Extra cities means extra research, and as long as you make sure your wars are reasonable quick, and you don't let your science slider drop below 30-40% you'll almost always be able to beat the other civs in tech.

You've got to learn the correct cycle between attack and develop. You capture a bunch of new cities, but making sure your science slider doesn't drop too low, and then you have a period of peaceful development in between to get the new cities producing a decent amount of beakers. After 3 or 4 wars, you always end up bigger, more powerful and more advanced than everyone else.