Cata is far easier than HW 1. Bar gimmick ships, Acolytes are so damn flexible that you barely need anything else bar capital ships.
So, hints. I never used corvettes in my playthroughs, but from some tests they seem to be effective (SCO was right about their use. Beauty of HW is using different ship combinations!)
My two cents.
Use Scouts (Light Interceptors!) as bait and quick strike force. Avoid Interceptors, they're not cost-effective. Small wings of bombers can be a knife for gutting tough foes.
Scouts cad do everything- harass, and in open formation and evade stance be vital to distract bigger ships until your salvettes (Salvage Corvettes) gang on them. 'Distraction' is vital for capturing.
Capture capture capture. Capture all the Turanic Ion frigates (they're slow as hell, but in Wall formation they are effective).
Kadeshi frigates are a blast- focus on them for capture.
The first real enemy in HW 1 is the fleet that destroyed Kharak- be slow and metodical with them, avoid quick attacks and slowly erode their numbers. I've never succedeed in capturing the Transport, though.
After that, HW 1 is 'easy'. You will have enough ships to take head-on big assaults and capturing even more of 'em, a snowball effect.
Use scouts and multiple salvettes as bait. Repair corvettes as support.
About Frigates, after a while I stop using them... Capital ships are enough to eradicate enemy capital ships,frigates&corvettes, while swarms of Scouts engage/distract the rest. Be wary of Missile Cruisers, if you follow a fighter-heavy strategy.
Other stuff.... Kamikaze is a good way to get out from bad spots. Scouts or collectors can do a lot of damage to specific targets, if you're in dire need (like if you need to blast large rocks in a hurry).
If you realize you failed to build/preserve enough ships, start again. HW has some 'breather' missions, but a ineffective fleet will doom you in some later ones,