I find it difficult to play in octaves with one hand in pieces like "Rondo Alla Turca" and I totally miss the keys sometimes, especially when trying to play quickly. I am 15 and my hands are averaged-sized. Does anyone else find this, or does anyone have any tips/advice?

Thanks in advance

I had trouble with that until quite recently, and I find that one thing that helps is to make sure your fingers stay the same distance apart, and just aim to get one finger on the right note- the other will follow.

It depends how big your hands are.
Im 14 and My hands reach perfectly from one octave to antoher, but it hurts after playing chord progressions for the house of the rising sun for ten minutes straight.

I suggest that you find which finger is the correct length.

If your hands are my size, use the pinky and the thumb.

If they are bigger, use the thumb and ring finger.

Get my point?

Make sure your hands stay close to the keyboard so you don`t have to move as much. The more you have to move, the bigger the chance of missing. Also you might want to consider playing black keys with your 4th finger.