Would it be fair to say your science speed was the limiting factor? If you identify the limiting factor you can understand how to speed it up. I would only have 3, certainly place one and build it when the university in that city is done but that will be at the cost of a science project and if science was your limiting factor. This is one reason why you only go the rainforest and artifact ones as democracy will halve the amount you spend on great people. Also more projects and earlier buildings means more GP efore you have to spend but I do not believe this is as important. It also seems culture may have been despite building the colosseum. The colosseum is more about the culture it provides than the happiness. Culture is also about getting to the double science adjacency card and more importantly the double science building card as well as earlier government and therefore card bonuses. Getting as many eurekas as possible really helps. For cities with just a campus did you place specialists in the library and university? You need to chop in campuses ASAP and get the CS up to 6 ASAP. This is a big jump in science time. Libraries are pretty cheap and easy to slot in after than. Its the universities you need to get in and goind as soon as you can. Did you get the markets and trade routes in before the eurekas? Chopping in pyramids is handy but not the end of the world.