If you shift your weight too far to one side, it is not possible to recover. Jump away from the board in the direction you are falling. This takes you safely away from the foil.
Keep your weight forward and press down through your front knee. Confirm your feet are in the correct position.
Don’t vary your speed. It will only unsettle the foil and make balance harder.
Like an aeroplane, the foil wings need a constant speed for smooth flying.
Don’t try and foil going too slow. The wings will stall and you will crash.
Don’t try and turn on the foil until you are very comfortable in a straight line.
Keep the board flat and level.
Foiling through turns
Turning while foiling requires careful balance on all axis.
Start by doing very wide turns.
As you gain experience you can try tighter turns.
Keep speed constant.
In tight turns you will need to apply more force to your back leg to maintain foil altitude (like a aeroplane adding elevator through a turn).
All of this might sound complex, but if you keep your weight forward, practice in flat water, maintain constant speed, and take learning step by step, you will likely be foiling in no time.