Dont worry about the bands really.
Your biggest needed items for breeding good competitive pokemon are the Destiny Knot, an Everstone, and of course, patience.
If you want to try breeding a comp pokemon, check this video out for pointers.
Then, of course, if you are new to the comp scene, this is a must...
From there, if you get any other questions, feel free to ask me. I have been getting much more into comps, so I can certainly give pointers or opinions.
However, if you decided to try and breed some comps, I would certainly recommend you save this for after you beat the game. I say that mainly not because you could use a beaten game to help (which is preferred technically, but you can breed before the e4 I guess), but I say this because you should first enjoy the game to the fullest. Playing competitively is not for everyone, but can certainly breath new life into an already beaten game, giving you more fun things to do once the game is over.