You don't suck, you just need practice, and to bear in mind that in some ways flying an aircraft on a PC sim is harder than the real thing.
You do not have half the feedback you get when flying the real thing on a PC for one thing, and you have no peripheral vision to help you in formation flying, you also cannot 'feel' the aircraft through the stick resistance and through your ass, so it's much harder to see when you are on the ragged edge in a sim.
This is one of the reasons why Track-IR is such a plus, as it it a big compensation for the lack of peripheral vision. Force feedback can help a little with the pre-stall buffet too, but most sims don't model this particularly well, so FF is of limited use
The trick to formation flying is the same as most tricks where aeroplanes are concerned (the trick being, there is no trick). What I mean by this is that the most important thing is to ease up on the stick, and let the aeroplane do what it wants to do to some degree. When you see war movies where some guy is learning to fly and you hear the instructor telling the guy under instruction to 'ease up on the stick', that's because this is one of THE most common mistakes when learning to fly for real, and it's also true in sims!
The next thing to bear in mind with formation flying is that your aeroplane has a lot of inertia, which means you have to think ahead for it a little bit, make small throttle adjustments and ease into position, but bear in mind on realistic settings that you will have to adjust the mixture on the engine as you climb (i.e. you must lean off the mixture as you climb to prevent too much fuel going into the engine as the air gets thinner while you climb, otherwise you'll not develop enough power). The upshot of this is that since your formation will probably be climbing en route to its target, you'll probably not get away with one throttle setting to stay in formation, even though they are maintaining the same speed. In real life when flying in formation, you can anticipate the movements of the aircraft you are staying with by watching his control surfaces, as they tend to move and take a while to actually have an effect on the aircraft, so that's another case where the real thing is easier.
Next big thing in formation flying is a reference point, what you need to do is stick your aeroplane on autopilot for a minute or two and let the A/P fly you into your formation slot, when you are in position, note where the nearest aicraft is, and note a spot on your aircraft's canopy which lines up with something prominent on the nearest aircraft. This is your reference point, knowing this you should be able to disregard all the other planes and just fly by using small stick movements and throttle adjustments to keep that bit of the nearest plane in line with that bit you picked on your canopy. Learn the reference point for another aircraft too when you've got that one sussed out, that way, you will be able to look around and stay in position, and this is also useful in case someone in your flight gets shot down.
If you drive a car, you can emulate this trick on a good clear stretch of road: if you look at the line at the edge of the road and note it's position as you drive along, you'll find that it is possible to keep your car straight by maintaining this line at a constant distance (don't try this with other traffic about, or you'll bloody kill yourself, or someone else! but it will illustrate the formation flying technique to you). The standing joke with this technique in real life is: If your flight leader flies into the ground, if everyone is doing their job properly, there should be three holes in the ground alongside his!
A slightly more advanced technique for formation flying is to line two aircraft up in your flight and keep one hidden behind the other, if you do that, you know that you will be in echelon formation with the other two aircraft.
With all these techniques, do not fall into the trap the RAF fell into in 1940, i.e spending too much time concentrating on the formation and not enough time looking for bad guys! for this reason, you would be better off learning formation flying in a Messerschmitt 109 or a Focke Wulf 190, as these aircraft are likely to be using the 'schwarme' formation, which has formations positions with less proximity to one another, this will ease you into the skill and still allow you to search the skies.
Rolling on take off is generally caused (in real life) by having a lot of rudder on at the point you lift off while you are slow (this is a big no-no in real life) as it can cause two problems. The first problem is that the big slab side of your aeroplane will block off the airflow to the wing on the inside of your yaw, as your aircraft skids along. When at low speeds, this means you are just above stalling speed with one of your wings getting a big portion of its airflow blocked off, consequently, the wing with a full clear airflow picks up, while the wing with the reduced airflow will be getting less lift and a disturbed airflow from the untidy air coming off the fuselage. Result, you roll.
Another cause for roll (not always simulated in flight sims) is adverse yaw, this is a problem more likely in larger aircraft with long wingspans, where the affect can be quite noticeable. Adverse yaw is caused by the increased lift of the ailerons on one side as you move the stick to the side. What happens is that as the up-coming wing creates more lift, it also creates more aerodynamic drag, which slows it down and yaws the aircraft in the direction opposite to the one you are intending to go with your roll. I would think this is unlikely to be your problem, but it's as well to be aware of the phenomenon, as some simulators do actually model this. Technically, the Messerschmitt bf 109 should suffer from this quite a bit at low speeds, as it had automatic Handley-Page slats fitted (which made it a notoriously crappy gun platform at low speeds in a turning fight), but I've not noticed this being simulated in IL2 to any great degree.
a third possibility for your carrier take off death roll may be engine torque. WW2 fighters typically developed anything between 1000 and 2500 horsepower. that's a lot of ponies. what happens is that as the thrust comes back off your propeller, it spirals down your fuselage ina big corkscrew pattern, which means that when it gets to your vertical stabiliser and rudder, it's pushing on one side of the tail and forcing you into a turn. As it does this, the wing on the outside of the turn is effectively travelling faster than the wing on the inside of the turn (think of the inside and outside lanes of a racetrack as a comparison to illustrate this). Since one wing is effectively going faster than the other, it will develop more lift, and as a consequence, you will roll in the direction you are turning. To compensate for this, you need to use rudder in order to keep you straight, but you must remember that as you speed up, your control surfaces become more effective (since air is passing across them faster), so, you must ease off on your correction as you pick up speed. Most WW2 fighter rudders were not actually symmetrical in order to counter this effect a little bit (most notably the bf 109, which had a tendency to go into a vicious swing on take off).
As with everything, practise makes perfect, but actually understanding what is happenning should put you on the right track fairly quickly. Remember, you do NOT suck. NOBODY was a brilliant flyer on their first flight, and anyone who says they were is a goddam liar. And it took me 7 hours and 15 minutes of instruction in real life before I went solo, despite my instructor saying that I was 'a natural', so that proves it.
Chock