Find your niche.
Hmm I have a couple of sites that I use for reference when I make tags and icons. Most of the renders and C4Ds I used come from either Renderat or Planet Renders, lots and I mean lots of stuff I just get from DeviantArt, a couple of icon tutorials from LiveJournal, tag tutorials from graphics sections of various other forums, while I get many gorgeous fanart stocks from Pixiv. A good amount of stuff I also got from users here at PC! I'd add more but it's way past midnight here and I really need to sleep, haha. I'll post again later, or maybe edit in what I forgot to add. (b'')b
I wish I had links ready but I don't, unfortunately. I'm gonna have to search them up again. D;