A basic sight in on the plane you want to fly is a good idea. Just like with a new pistol or rifle, the first thing you do is go to the range and check your sights against a target, not go out in the woods and go hunting.
In AHII you do that with the .target command. It creates a target at various ranges for you to practice shooting at. The format is .target xxx , where the xxx is the range you want to shoot at. For example a target at 500 would be .target 500. The target is always due North. Don't forget the space between target and the xxx.
You can shoot until the target fills up with holes at which point it will refresh itself, or you can use .target 0 to get rid of it, then .target 750 to put up a fresh target.
The target is useful:
1) For setting convergences.
2) For checking where you print between cannons and machine guns.
3) and my secret of the day, where your weapons hit at different altitudes. It is little discussed, but your weapons have different range and drop depending on the altitude you are at. AH models air density. The air at Sea Level is thick, therefore your total range is shorter, and the rounds drop quicker. At 30K the air is very thin, your total effective range is much farther and your rounds fire much flatter. To really see this take up a 109 with the 30 mm spud cannon. At sea level the rounds drop out on the ground in front of you . (OK, an exaggeration). At 30K the spud gun has an effective range of 1K+ if you practice. However this works two ways, a B-17 tailgunner's 50 cals have a tremendous effective range at 30K too, close to 2K. (if they know it).
I discovered the altitude difference after chasing a P-51 at 19k. He was flying perfectly level trying to out run my D-9. Range 700. I had practiced a ton at 1K altitude on the target and knew exactly where to set my sights to hit with my machine guns at 700. I blasted away, missing with every shot.
So I logged off to offline mode, flew up to 19K, set the target to 700 and blasted away using the "correct" elevation adjustment. I discovered that I was shooting WAY over the target center. My rounds were flying much flatter at 19K, therefore needed less elevation adjustment.
Be sure to get rid of it before you log in the main, or you will find a target floating around due North of you.