>>21056495Ignore breeding and IVs first, just go on Showdown. You can't make up new teams fast enough on cartridge to actually practice. Plus Showdown has better matchmaking and is much faster, getting a lot of experience in to learn the top threats, what they run, etc... is important.
Also, ditch any preconceived notions of legendaries or bros. I mean, I know this sounds strange, but you really need to start working with proven good Pokemon before you can really start to experiment and bring in other things. That being said, keep your team pretty volatile. Switching out lots of Pokemon can help you understand how they play, and what their strengths and weaknesses are. You're not really going to learn if you pick out a few Pokemon you like and then refuse to change them out of loyalty.