As an IJN DD player, I prefer going into caps first, but staying near the border. That way I can still try to cap, but Im also in a position to spot/smoke for my allies and still able to leave the cap if resistance is too great. Once we take a cap, begin work on spotting, attacking captial shipping, smoking allies, etc. as required.
My preferred doctrine is that if you have 4 DDd, you send DDs to two caps in pairs. If you only have 3, then send the most self-sufficient by themselves. Soviet and American DDs are great at killing enemy destroyers, but they need that first strike, which means they need a spotter. Any underage boats we can sink on the enemy team make all our jobs much easier.