I was in the same boat as you for a long time. I didn't like what was posted on the trainers page about combat landings because it presumes a much higher level of skill than I had at the time. Way too much to keep track of for a true newbie. Here's what I suggest:
Use the A6M2 (Japanese Zero) and fly it offline, and practice landing in it. Its one of the easier taildraggers to land, and it moves slow so you can get the fundamentals down while thinking about them (before they are instinct).
In the A6M2, all you gotta do is cut the throttle near the runway, and while gliding do some turns and use the rudder to slow yourself down.
(If you have rudder pedals, it'll be a huge help, because "sliding" your plane by full rudder one way, and pointing the nose the other way, with the intention of flying the direction that's in-between, is one of the best ways to slow your plane down quickly in Aces High.)
But either way, throttle to minimum and glide until your speed is a bit under 200. At this point you should be able to lower your landing gear. Having landing gear out slows your plane down a lot... you'll quickly get slow enough to be able to lower your flaps. Get your landing gear out, lower your flaps completely downwards. Then go back to full throttle. Because of all the drag of your flaps and landing gear, you won't be able to achieve more than about 120 MPH in this configuration, even at full throttle, unless you actually dive towards the ground. This is important because if you go too fast with landing gear out, you'll rip them off!
Now landing is easy. Fly the plane to the end of the runway, turn so you're going along its length, and put the plane close to the ground, cut throttle and guide it down gliding. If you overshoot, just hit the throttle back to max and make another pass. Once on the runway your plane will eventually stop by itself, but to speed up the process (and so you don't overshoot the end of the runway), use the wheel brakes (I think it defaults to the spacebar).
Now here is the key thing that was the least obvious to me that I had trouble with until I learned the trick... when your plane is on the runway but still going pretty fast and you're slowing down with the wheel brakes, your plane will tend to flip onto its propeller. Because its just a video game, you can still get a successful landing like this, but its pretty embarrassing. This happens just like if you only used the front brake on a bicycle, you can flip over the handlebars. You need to hit the back brake too, but your airplane doesn't have one.
The trick is to pull the stick backwards. They say this is to "lock the tailwheel", but that phrase didn't mean a lot to me when I heard it. In reality you're putting downforce on the tail of your aircraft, just like the spoilers on an Indy Car prevents them from flipping over. That downforce counters the fact that you don't have a rear brake. That way your plane won't flip over even when you're using the wheel brakes, and you can slow your plane down to a stop.
Once you get good at this, head over to the trainers site linked in a previous post and get good at landing in the usual way, using throttle to control decent and with the turns to bleed speed. This is important for landing aircraft not as easy to land as the Japanese Zero, and its important for getting on the ground fast when people are trying to shoot you down. Its just a lot to keep track of until you have some feel for landing, in my opinion.
Now realize I'm not teaching you good habits here. This is just to get you some confidence and more importantly, experience. Typically its not a good idea to teach habits other than good habits, but honestly they didn't work for me in this game, or weren't described well enough, especially the "how not to flip over on my nose" part, and why pulling the stick back works.
Whatever you do, if you subscribe to the game, the trainers will get you going. Rolex helped me a ton.
