but it looks like i am too bad to manage Defend Caspian IV ON EASY :(.
I dont know what to do.
I have some cruisers in the front of my fleet with high shield power to protect my anti fighter frigates and my 1/2 laser 1/2 rocket cruisers
and I also have a torpedo fighter on each “shield cruiser”.
I am not even able to get them under ~95%.
It seems to me that i am too unable for this 
Can someone give me a hint or a trick how to master this?
This level has a lot of enemy fighters to deal with, and I’m guessing its the fighters that are giving you the most trouble. Make sure your front-line cruisers have at least 2 or 3 strong armor modules, because laser fighters can shoot them within the shields. Then you need to have several tractor beams either on cruisers or frigates to eliminate the fighter threat. I used dedicated anti-fighter cruisers spread behind the front line of heavily shielded and armored cruisers. I used frigates to provide firepower from the back line. I also gave each frigate an emp missle and set the order to “Rescuer” to help reduce incoming fire on my cruisers.
Other thing that may help is making sure your targeting priorities are set appropriately for each type of ship. If you notice some ships going past the front lines and getting rocked, adjust their speed or change their orders to escort or formation to somehow keep them behind the front lines.
I wouldn’t recommend torpedo fighters for this scenario, they would be easy targets for all the enemy fighters. Maybe with an escort order and use of the new cruiser bays, an armored torpedo fighter could get their shots off as enemy cruisers / frigates approached and would repair as needed.
Lose the torpedo fighters. Use fast laser fighters instead, these can deal with the enemy fighters. Let your cruisers pound the enemy. Fighter torpedoes aren’t that great. They can be useful, but usually you have to plan pretty well for them to do so (i.e. time it so you’ve already wiped out the enemy anti-fighter cover before they engage.)
The speed control is your friend. Turn the game speed down to 0.2 so you can see how your fighters are doing. Are they getting chewed up by the enemy fighters? Why? Are they slower than the enemy, or are they just getting shot up by lasers while waiting for a slow weapon reload?
Weapon effects come out of the correct turret, so watch carefully, are your beams that fire from the left of the ship always bouncing off? If so, mount something else on the left side or put that kind of weapon on a ship that is positioned to move in for the kill with vulture orders after something else has cleared out the shields.
Watch what happens when enemy fighters get inside your shields. Do you see little red ‘pings’? Those are (mostly) harmless. Do you see little explosions? Danger! That means you’ll be needing more armor!
Basically, the game is mostly about throwing stuff out there and then watching the pretty battles with an eye towards tweaks and improvements. I could go on and on about what works, but it’s a lot more fun to watch, learn and improve. If you are still stuck, download some challenges to get ideas about what other people are building.
Finally, the stats screen is your friend. If you have fighters that get hit 50% of the time, then your fighters are too slow. If your weapons miss 50% of the time, then you’ve probably issued orders that prioritize ships that are too fast to hit reliably (ie, your cruiser is choosing to try to dogfight the fighters. Imagine trying to hit a mosquito with an axe.)
A VERY, VERY, easy way to clear the campaign is basically to spam a single cruiser, and have a large group of tutorial fighters escort them. I was basically able to beat… every single campaign mission (on easy) in that manner. Once you’ve done that, you can go back and start working on “really” playing the game (especially as doing so allows you to unlock the large majority of things that require honor).
The cruiser I used was:
Federation Buffalo Cruiser Hull
3x Shield Generator 2
3x Fusion Beam
2x Cruiser Engine 2
4x Heavy Plasma Launcher
1x Power Generator 3
2x Basic Power Generator
1x Crew Module 3
2x Cruiser Armor 2
Before anyone comments, yes, I’m aware that this is… highly sub-optimal, etc. etc. It’s just a very simple, very easy way to clear the (easy) campaign quickly and easily, while generating a pretty good reservoir of Honor. You can actually start playing the game after that.