It appears that you are having trouble with the basics of flight, something you have to master before you really settle down with any good flight sim.
Take offs are not too hard, slowly push the throttles up to full power (or after burner) set the flaps down, release the brakes and wait till the plane's nose starts to rise (basically the plane starts to lift itself off the ground). After that pull back gently on the stick and airborne. Raise gear and keep the flaps down until the plane has gotten enough speed and atl (basically when you feel like you are high enough)
*Once you get use to takes offs you will be able to better gauge the plane's speed and the length of runway the plane needs to lift off.
My suggestion is go into the game options and have your plane start on runway, set gameplay to easy, and fly recon missions from the drop down mission type list.
After you get use to handling the planes and how the workings of the game, start setting the game options to "normal" or "hard" one by one.
I must warn you that some 3rd party/downloaded planes operate better with "normal" flight model selected in the options menu.
The best advice I can give you is that pulling back hard on the stick and trying to corner them like they are modern fighters with digital flight controls (ie F-18 or F-16) will get you into a roll, buffet, or stall in a hurry.
Once you start flying other planes in the game, especially the F-4, F-104, or F-105 you will find that speed is life! They are not nimble, but they have a lot of power and can climb very fast in a hurry. You will also find that with weapons and gas they use a lot of runway to take off and land.
Dog fighting is an art in this game. You do not have load out of a modern fighter, nor the computers to help you out. You don't have the gun coverage of a P-51 or the turn rate of FW-190 (at least stock without mods). However what you do have is speed and power. You can disengage and re engage into a fight at will. You can climb very high and go very fast down low. Your missiles are not going to track like a modern Aim-120C and you have to be in perfect piston before you get tone with an older Aim-9. (Forget about it with a Aim-4 ). The migs can out turn you, but you can out climb and power them. The heavy American planes bleed energy in turns but pick it up much quicker. Even the fast AI Mig 21 (which was one of the fastest fighters of its time) can be over powered and out paced.
Just take your time, be patient, and have fun. You will get the hang of it in no time. Do not be afraid to ask questions, someone around here almost always has an answer.
Good luck and be easy.