Some suggestions spring to mind:
1) High-IMP and -DMG weapons are cheaper than multiple 1/1/1 weapons, but on average let you roll the same number of dice.
2) Fighters!
3) Increase the number of ships on your side -- instead of smaller numbers of high-value ships, go with larger numbers of lower-value ones. This will force your opponent to concentrate his attacks, and potentially waste some of that firepower on "blow-through" or else split his attacks and thus increase the chances of poor dice rolls.
4) Fighters!
5) Floating game board. Makes it much more difficult to adopt the "sit in the corner of the map and blast away" tactic.
5) Did I mention fighters?
One thing that came up during discussions on the Admiralty Edition was the possibility of "weighting" the cost of firing arcs based on their position: e.g. A/B arcs would cost 1.5; C/D arcs cost 1.0; and E/F arcs cost 0.5. I rejected this at the time, but maybe it's something to consider...