Galio jungle is fun but hard to capitalize. Clearing jungles camps are very hard, but ganking is easier. You still need to try to get the most jungle camps as possible to not get out lvl in the game. Try to wait the later possible to take your first spell, cause if ennemy invade, your W is very strong and can give you an advantage to counter the invade and even try to reverse the situation. Taking tank galio is the best choice for me cause you always have a lack of engange tank in your team comp. Ap galio jungle can still be good but only if you have at least 2 tanks on your team.