grouping you planes works best for DB, if you press ";" (i think thats the
default button ) and left click you'r bombers will start making a bombing run
and group up. the closer to you bombers you set it, the earlier they group up.

once they reach this spot, they'll make the dive you asked for.

its all part of the manuall dive bombing system.

also a nice part of this move; if your at low altitude (to prevent AA) you can get
your bombers up fastest with this tactic. (but if holding the "raise alt" button
you can also use auto bomb below max alt).

for fighters and TB its all up to clicking at the right spot during their circeling
(easiest on lift off)

For the bombing tactic search "manual dive bombing" or just "manual bombing". It
might even be in one of the stickied cv guides.

As for grouping your planes just click ahead of them on the flight path not too far away
in front of them and they will all fly to the same spot. Basically right click in between the
planes flying in the outermost of the cluster to get them to fly closer to the center of the
pack. For better results mash and spam click.