I'm going to parse out your last post as there some points I want to address specifically, but I will make an overall generaly comment:
Your game is not going well at all and you should be in a far better position on this level...I say this though knowing that you have little experience with Civ IV or really learned the game...that is what we are here for
.... Noble level for a few games and I usually wind up in the middle of the pack.
We can help with that immensely in S&T
I figure I must be doing several things suboptimally.
You are doing many things suboptimally
In particular I'd like advice on how to use a Great Person economy effectively -- I find that even when I focus on farms over cottages (as I have here), I don't have enough hammers and light bulbs to spare to invent the techs and build the Great-Person-boosting wonders fast enough to get them before the other civs do.
Forget this stuff. Wipe it from your mind. I assume you read some old article or something on what we called the SE economy (Specialist Economy). First, that has largely been debunked in recent years but otherwise is a very specialized way to play that is not conducive to learning..it's quite advanced.
The common optimal/flexible and easy approach is the "hybrid" economy. To point, Great People generation is always very important and understanding how and why, but cottages are still very important and powerful. Especially the Bureau cottage cap. But ultimately, you play the land and what is best suited to it and gives you the best success. Land can obviously fluctuate quite a bit depending on maps and stuff. As you learn you will be able to handle these situations better.
Like in this game I rushed to get Great Lighthouse and Colossus first, which worked well, and my economy has been fine as a result, but that didn't leave me any builds to get any of the Temple wonders, and I only just researched Literature a couple of turns ago (in 1500 AD).
Well, GLH can be very powerful and should be strong on a Medium and Small map or any more watery map. Colossus too. Your game is late so I can't really see all the early steps you took to do this or that (well, with time I could kinda but I'm tired ..ha)
Not sure what you mean by didn't leave me any builds to get any of the temple wonders, but that sounds completely irrelevant.
Literature in 1500AD? Well, your tech pace is ..comparatively speaking..really bad here based on the benchmarks that I know..just saying. Again, seems you are harping on wonders in general here which is really not what you should be doing. Certain wonders are built based on certain conditions but just all out build wonders to build them is very suboptimal. It is really not a discussion to be having if you want to learn. The first steps most will teach you have absolutely nothing to do with wonders.
There's always so much to do! I'm usually either at war and need every unit I can scrape together, or playing infrastructure catch-up after a war and trying hard to build enough happiness and culture to stop my cities from revolting or starving.
The more you learn the more you will find out that there is not as much to do as you perceive. I mean there is always something to do, but you get better at balance and knowing when and what to build as opposed to just building everything.
"playing infrastructure catch-up " This is not a thing..ha. That concept does not exist in this game. Really there is only one required building in this game - the Granary. Everything else is situational. I realize this probably will leave you shocked, but again you will learn with more advice and eventually understand. I'm too tired to go into detail on this and it is better to learn this stuff while playing and getting advice from experts...like in a shadow game over in S&T.
happiness and culture? again, you will learn how to manage this things. I'm certain you are not using the whip effectively or at all.