Dogfights can be tricky, especially when fighting against a russian Plane or an experienced player. When you have problems with this, try to destroy gound ground targets and place hitmarkers on enemys. You should use a plane with has bombs but is also suited for air to ground, like the BF 110 of the german tech tree, or the Ju 88.

Mostly, you will be fighting in a match where you have to destroy three enemy bases and shoot down enemy planes. The first one who drops a bomb on a base gets the points! So go for the closest enemy base, they are marked so do not worry. Then just drop one bomb or two, and focus on nearby ground units like AA or Tanks. The lower you fly, the more accurate your bombs. But watch the ground, don't crash. 200 meters above the ground should be the limit. You can easily farm some points that way, without struggling with PvP dogfights.
Do not forget to hold down C to look around freely. The Y button zooms your targets in, very helpful. Once you are out of Bombs, use your machine guns and cannons for Air to ground! And always watch your altitude, go to like tree thousand meters, and then press shift to strike down onto your target. Do not descend by 90 degrees!

Again, try to gain altitude, and do not fly straight into the enemy formation. Try to go for big targets in the beginning. You can increase speed with shift, but do not keep the engine that way for too long. Tap ctrl (strg) once, to decrase the engine power to 100%. Let your marked enemy pass you, then you have to get behind him. Try to get your crosshair as often into the circle which appears in front of your target as possible, and shoot in short bursts of two seconds. Try to hit him as often as you can, because when you die, you will still get the kill once this player crashes. When an ally shoots your target down, you will get support points, if you shot the enemy before. Attacking weak enemies can also award you points.
Do not just fly with the mouse, use WASD as well.

Keep moving, use boosters (They EXPIRE after THREE DAYS), use artillery strike on flags which are being captured by the enemy or use on spotted enemies. ♥♥♥♥ is for aiming, Y zoomes the crosshair in. The mouse wheel is for small zooms. Try to have cover nearby, do not drive across open areas. Capture flags. Move your tank to decrease the turrets rotation time.