Agar tutorials?

Just getting into AGAR these last few weeks with some MSS and I've realized I have NFC what I'm looking for in the cups after growth starts. I can reasonably conclude that green=garbage, but after that I'm an ape swinging a club at the dirt.

Are there any tutorials out there that would detail what I'm looking at in my various cups? I just today read a comment about "you only want one colony per cup" which blew my dick off. It didn't even occur to me that a MSS could lead to multiple colonies fighting each other in a single cup.

What should I look for? What should I select for? What's bacteria look like in early growth stages versus early myc? One drop from a MSS per plate? Etc. Some of my cups have what I can only describe as a "flow" of white stuff in the middle of other white stuff. Is that bacterial? Is that two distinct colonies fighting it out Gangs of New York style?

TIA.