When your in a destroyer you need to be looking at the minimap even more obsessively than normal.
I highly suggest that you check it multiple times as you get ready to drop. Especially as you get into Torps with greater and greater range.
Torps are not a precise weapon by there very nature and once you fire them they run there course regardless who may be on the receiving end.
As a DD main I would also suggest letting your team know if torps may be ANYWHERE NEAR them. I normally type "TORPS INBOUND! From LEFT (or whatever direction they may intersect with your teammate.) This way they may be able to dodge, stop, tactically beach etc.
Just remember at the end of the battle you are responsible for each torp fired. Make sure you have looked at the pathway of it before you "let it out into the wild."