Make sure the carrier travels in a straight line while you want to take off, can see that in the clipboard.
Apart from that, use full power and one notch of flaps, plant the tailwheel locked pulling back on the stick till airspeed is 60mph, let go on the stick and keep it straight. Use your rudder to keep the aircraft straight, slip indicator should be right in the middle the whole time.
Try to take of with a seafire Mk 2 or a A6M5. Start with 25 percent fuel and no external stuff.
When your plane goes backward you have only applied a bit of throttle, not full throttle. Apart from that you must not use the hook, its for landings only.
Also, when you land on the carrier remember to retract the hook after landing and have 0 throttle to use the wheel breaks. Not retracting the hook will shoot you off the carrier.
What plane did you have the problem with? You got it filmed and can post the film?
For taking of b17s, need a runway where there is no obstruction at the end of the runway and long room till hills. Best to take off in direction of the water. Use 50% fuel.. will get you everywhere. You can take off with 100% but its harder and most of the times not necessary.
Spawn the B17 on the runway.. hitting SW, SE, NE, NW button whatever gives the least obstacles. Start engine, apply full throttle and keep it straight on the runway. Notice you can raise your seat with Page Up key for better view, or fly with F3-View.
When half way down the runway apply one notch of flaps, when at the verry end of the runway pull up verry gentle to lift the plane. Get up the gear and hold the plane level, accelerating 5feet off the ground till you have enogh speed to climb (160mph).
Now, try that, if it doesnt work feel free to post again in the threat and say exactly what problem you encounter with which plane. Maybe someone else can give a more exact description on the takeoff or has some more ideas.