ACRO Basics: Hovering
When you first think about hovering it seems trivial, but when you first give it a go it can seem impossible. There are two simple aspects that can initially catch you out. The first is that in acro mode the quad is not self-leveling and so if you over correct this can lead to pilot induced oscillation. So keep your corrections small and controlled.
Secondly, you need to remember that your camera is not flat in the quad but is angled slightly upwards. Typically this is by between 20° and 45°. In the hover this will result in your camera pointing very slightly upwards, although this makes forward flight easier. Consider starting with a 20° camera angle until you get the basics down and then play around with the angle until you find what works best for you and the tricks that you like to perform.
When you first take off you will need to raise your throttle until you take off and gain altitude but will then need to slowly reduce the throttle as you approach your target altitude so that you do not overshoot.
Note that in the video below I am not just inputting throttle but instead balancing the throttle, pitch, roll, and yaw, with very small movements. When flying outside you will also need to counter the wind.