I play on Noble, and I always seem to *just* behind the AIs on tech. Whether I play financial and try to stay peaceful, or play aggressive and try to take over the world, I can't seem to build a comfortable tech lead.

I use quite a few cottages, and I try to be the biggest civ whilst still having 70%-80% science. I build libraries/unis/observatories in basically every city.

Can anyone give me some tips? I don't want to be constantly behind, I want to be constantly ahead, so that I can move up difficulty eventually!

If you upload a mid-late game save I can help you.

Cool! I am actually starting a game now, and I'm going to try my damndest. I will upload at around 1200 AD or so.

You don't need a library in every city. There are many instances where it is better to specialize the city. If there are many hills nearby, or good sources of production make this a military city. Build Heroic Epic, and crank out units for your war machine. It is a waste to build a library in this city if you are only producing 3-5 beakers anyway. If the city grows later to the point where beakers are substantial then you can build one later.

I have found that using Scientists is the best way to stay ahead in techs. Build a library in a town with lots of food. Convert two citizens to scientists, giving you 6 beakers a turn. You are also getting 6 Great Person points. When you get your Great Scientist use him for an academy in your largest cities, or just burn him to get a free tech if you need it. Often you can use this free tech in trades with AI to get others.

Lastly, get the Great Library. One of the most powerful wonders in my opinion. In my current Noble game I am running the civ for unlimited scientists and built the Great Library in a food heavy town (but clearing ALL of the nearby forests to rush it). I had the following combo going in the middle ages:

4 Scientists - 12 Great People Points
2 Scientists from Great Library - 6 Great People Points
Great Library Produces 2 Points I think?

Base of 20. I had National Epic? built that doubles points in this city and had Parthanon in another city. Was getting 50 points a turn around 1100AD.

When I got this running I think I was needing about 500 points for the next Great Person. It took me only 10 turns to get him, then 12 turns later I had another, then 14 turns later I had another. I burned EVERY one of them for a free tech, plus I was researching this whole time so I raced through the middle ages. Was able to land Liberalism for another free tech.

What about trade or tech for tribute? I only play at noble too, but this is the most common suggestion for teching. In other games (Galactic Civilizations comes to mind) tech trading is huge on the lower levels. But you seem to have to have parity with the AI for techs, ie you research tech A, trade them for equal tech B (equal in cost). So it's hard, if you are behind, they won't trade. If you are ahead, you don't want to trade. Maybe getting friendly with tech leaders would help.

I find I can trade techs to civs I just conquered in return for peace fairly easily, so keep research high even during war.

Also, you can try being an industrius leader and get the statue of liberty (free specialist in every city), mercantilism civic (free specialist in every city but no foreign trade routes), and representation (+3 science per specialist).