How to Group

Just do it. Don't stop for that 150 gold. Don't stop for that red buff. Don't go bot lane to clear wave.

After baron, you have two options as a team. All 5 immediately go push, or all 5 base and then immediately go push (keep in mind the previous line).

This will win you a lot of games.

Free extra tip: base as a team when it's time to leave.