IJN carrier player here too!
With the Zuiho I used my fighters to scout for enemy destroyers and cruisers, and then proceed to delete them if necessary. At times, I gave air cover to lonely ships.
I have just bought the Ryujo, and at tier 6 the carrier scene seems to change. Given the ridiculous amount of AA firepower at tier 6+ ships, especially cruisers, I tend to conserve my strike teams for later in battle, when enemy cruiser fleets have thinned out, and give a heavy emphasis to scouting early on. I still try to strike exposed targets of course, but if that is impossible I try to provide vision and air defence until I can start swarming isolated warships.