How to improve your Downward-Face Dog Pose? If you're beginner I'll give you few main tips! 

Step 1.

Make sure that you perform it with correct distance between palms and soles. You can ask your teacher to show you the proper distance or you can measure it yourself. 

1. Place your big toes together, knees slightly apart and put the buttocks on your heels. 
2.Lean your body forward, try to move your palms as far as you can keeping your buttocks in closer to your heels. That's the perfect distance! 
3.Now keep this distance and get your buttocks up, tuck the toes and get up to#adhomukhasvanasana with the perfect distance!

Step 2.

Be aware of your palms position. Put them equally parallel to each other, spread your fingers as wide as you can. Keep your palm and all the fingers totally on the floor. For beginners this pose more like handstand and less standing on the feet, that's why be sure that the base of your pose is properly aligned.

Step 3.

Don't let your shoulders squeeze  your neck! Try to liberate your neck by rotating shoulders from inside out and moving them away from your neck. Keep your neck relaxed, let the head hanging between your shoulders.