I find that the main issue with a lot of iron golem farms is the collection systems. The top layer, where you place the igs, is pretty simple. You mainly want to space them two blocks apart in every direction, so the igs have enough room to spawn. Something like this:
After you get that, the water collection system is up to you. I personally use this design:
I have four quadrants of these water collection systems, which all lead to this:
The hoppers all lead to an infinity chest, which auto sells all my items. In the case that you DONT have this, a system, I'd be happy to give anyone a design.
Overall, the most important part in my opinion is hoppers. If you mess up one, then it could be all over for your farm, haha. I recommend putting running water over them, to stop the items from despawning.
This is just my opinion though, and as other people have said before, there are many different options! I wish you the best of luck!
Best,
Wingy Bnoi