Since you are on the newer side and might not have the currency for IOs, here's my general rule for starting out.
For Single target attacks you want 1 acc, 1 end reduc, 3 damage, 1 recharge.
For AoE attacks you want 1 acc, 2 end reduc, 3 damage.
For virtually any toggle, you want an end reduc in it.
If you are under level 22, double the number of slotting for what you have so lets say 2 acc and 2 end reduc. BA is fantastic, but is absolutely sucks end. I would also do this with common IOs. You can use level 25s all the way to 50.