Building Gaming PC Help

Hi, I'm trying to build my own gaming PC for the first time and I need some opinions on what to buy. I've never had a great PC before, so even though I have an idea on what is good and what isn't, I still don't really know. So far I've mainly been looking at graphics cards, but I also need recommendations on stuff like CPU's, motherboards, memory, cases, power supply, etc. 

From what I've see