There are a couple I suggest, if your are F2P then train on white knights, if you are P2P train on Yaks (If completed Fremennik Trials quest,) or train on Rock Crabs.
It depends on your combat lv.
train a wailmer to lv 40
lesser demons im a lv 89 and i train on black drasgons dont do anything you might regret like tasking ur best armr and dieing like i did stik to lv 60s and 70s enjoy the game
You should train somewhere in the water maybe.A perfect place might be pacifidlog town or sootopolis.you will find lots of trainers.have fun
it doesn't matter were you train it
train your weak guys and i t will be easier and when staravia evolves he' s a tank ALSO TRAIN YOUR POKEMON BECAUSE YOUR POKEMON ARE WEAKLINGS I CAN EVEN BEAT YOU UP
40 or 50 Rayqauza - lv 70 Groudon - lv 45 Regirock - lv 40 Registeel - lv 40 Regice - lv 40 Latios - lv 40
In and around Peach's Castle. :)
It evolves at Lv. 24 but since you caught him at Lv. 24 train it to Lv. 25 and he should evolve.
Train, train and train!
you should train in stark mountain if you have batteled every one use the Vs seeker if you don't have it just train with wild Pokemon
get the next gym badge