I suggest leveling Archer up, if you haven't done so, to get Raging Strikes and Quelling Strikes. The former is a good buff to your damage whilst the latter is great to pop at the start of any skirmish to help ease on dealing with aggro. There's no real hurry to get them, but if you're planning on staying BLM for the long term, you will want to get them eventually. Sleep is very situational, so I wouldn't worry too much about it. The main uses of it are if the tank or healer is down and you need to regroup or if you're speed running Wanderer's Palace which is endgame dungeon. As mentioned before, it can also be used if the tank or healers feel like they're being overwhelmed.