Bounties are basically extra objectives for you to go for while you are playing... so pick some that you should be able to complete (so if you are doing crucible, don't bother picking up PVE bounties like killing x hive enemies or completing public events, etc). Other than that make sure you turn your mission items in if you got any (you'll have markers on your map to go talk to whoever to turn it in) and have the cryptarch identify any engrams you received. Check the gunsmith if you feel like it for weapons, but thats about it!