This thread is kind of hard to follow. You establish knowledge of econ, ship mechanics, and viable strats, and then you assert that they are all useless. They are not all useless, and the econ/ship info is quite important to success. From here I'm guessing your problem is in execution, so I'm going to give some basic tips for fighting AI(s?)
1. Expand as much as you possibly can very early. Planet bombing is limited in the early game, and 1-2 turrets will fend off most harassment. Unless the map is quite small, (15 planets or less) start off with the Colonizer capital ship. Reinforce it with ~10 frigates and just take every neutral planet you can. Generally the first things I research are volcanic and ice colonization. Build at least one colony frigate, too, and capture any neutral astroid field mines. This is important to early game econ, do not underestimate it.
2. JRM frigates are only any good for the first ~40 minutes. If the game gets to be an hour long, you will be best off with heavy cruisers, flaks, a few Hoshikos, and capital ships. Fighters (on your cap ships and hangars) are better in the early game as bombers only excel against heavy cruisers, caps, and structures. Bomber carriers are good in the late game for razing orbital structures and ganking capital ships. The Armistice ability on the Colonizer cap is a huge boon to fleet survival. Just dump that in any fight you won't win, and escape.
3. Build orbital defense structures. Lots of them. The AI tends to over-upgrade the fleet cap techs, and I'm guessing from your plea for help that you do not wholly optimize your economy. This is the best way to keep your planets defensible without having to invest in such a high upkeep. Also, build a media hub (culture building, forgot TEC name) at every planet.
4. Organize your fleets with direct DPS ships and your capital ships on a hotkey. Start the fleet with a capital ship so it is the focus of the fleet arrangement. Keep your support ships and your flaks in the fleet, but not in the hotkeyed group. Put all the ships in the fleet in Hold Position, and set the fleet to 'All tight'. Now, the flaks and support ships will automatically stay with your capital ship, even through jumps. You can focus fire with your primary dps ships without worrying about the flaks and supports wandering off. Eventually you'll micro more, but this is quite sufficient for AI.
5. The easiest way to beat AI is to expand early, build up planetary defenses, and suffocate their meager econ. They tend to shoot right up the fleet cap upgrades into a huge economic upkeep that is irreversible. At this point, trapping ships with phase jump inhibitors and killing the colonies far from their main fleet is crippling. Eventually you'll start to out tech them and be able to support a crushing force that their current ships cannot handle, and with an econ that can't fill the holes.
I have more, but I'm rambling already
More specific questions might help.