Aside from mastering the game mechanics and Basic Flight Maneuvers (basic skills), there are advanced skill sets.
The detailed list would be very long, but it starts with Situational Awareness. Everything else is born of SA. Using the map to determine where and how many enemy are in your sector and surrounding sectors. Using the map to determine where the nearest threat is. Using visual observation where the actual enemy is relative to you, while determining his E state and the level of threat. Doing this for multiple enemies within visual range is essential for dealing with all of them effectively. Of course, SA is equally important on the offensive as well as defensive.
Command of Air Combat Maneuvering (this is something you cannot learn without practicing... Read Shaw at the very least)
Accurate judgement of enemy E states (without this ability, you cannot assess threats reliably)
Wingman tactics (learning to fly effectively as a mutually supporting team)
Mastery of aircraft (knowing the true ability of your aircraft, even every aircraft, and being able to exploit strengths and avoid weaknesses. Being able to exploit the weaknesses of the enemy aircraft)
Gunnery (the best killers are usually the best shots as well)
Last thoughts: Concentrate on being as good as you can be, without comparing yourself to others. Some players have a higher talent level for this than others, just like in athletics or academics. If you find yourself dwelling on others, you will enjoy the game far less. Few, if any of us, have the talent to be professional baseball players, but we can certainly enjoy the weekend softball league and have fun. So, above all... Have fun. Just remember that a little practice and skill development can add to that fun (just like playing softball).
(edited typo)
Longtime no see all you AH Addicts!!! Aloha!
spoton and to the direct point Widewing, Sir!
also like what Corky/Guppy/Tiff posted and as well, Big Rat's follow up
cheers all, Happy Memorial Day!
TC ( Johnny )