You can get more trainer to train your pokemon, go for the lengedary pokemon, fight the e4
for once more.

This I will do after the e4.

go to skypillar go to the uppest floor than you can catch rayquaza if you have defeaten
the e4

complete the dexter, n theres a game freak dude in covelily of lilycove and he says if u
complete the dex, find him. i never complete b4 so i dunno. or battle til u find its
boring den restart the game n play again.