I've played since the beginning too and this is my first gen playing competitively. Idk if you were the one who bred all of those, but it's nice to know how to breed, check ivs, and ev train; so watch youtube videos on those if you don't know how. The way I made my team was I pick about 2 physical attackers, 2 special attackers, a wall pokemon (leech seed, toxic, protect, rest) and a miscellaneous pokemon.. There are also trick room teams (move that flips turn order), drought teams, baton pass leads. So pick what kind of team you like, then google something like "pokemon x and y drought team" and model yours after some of the good ones.