One tactic I've been using is transport raiding.
I push bombers to 4 (with advanced station) then build absolutely all of them.
Then I pack all the bombers, plus all my fighters and frigates (and tanks if you have them, or anything else heavy) into a transport fleet (maybe 10 or 15 transports for the whole thing).
Since the transports can blockade-run past the AI's defenses, you can run your entire packed fleet into the AI home system and then unload all 1,000 ships or so directly onto the final station, ignoring everything else in the system. Then you pound like hell on any shields protecting it, and on the station and hope you can do all 100,000,000 or so damage before the fleet is wiped out. Keep the transports there as well, they can act as decoy targets that will soak up a ton of damage.
It also helps enormously to not take the system next door.
You let the transport raid skip over the planet before it (which will be heavily reinforced) and land the transported fleet before the AI has reinforced the home system too heavily if at all.
Note that losses could well be vicious doing this even if you succeed, and for the first AI you might need to survive the backlash almost entirely with towers alone. So pack the hell out of the raid entry gate with defenses, and reserve your low-health mobile ships and any starships for only dealing with the subset of attackers that can evade tractors.