The main thing is to keep your playing fresh. I loved Mrs Corr's idea of getting your instrument out for a good practice on the day you usually would have your lesson! Even write down what you did and then next time do something different!
Mrs Bennett our cello teacher suggests adding some dynamics to make your piece more interesting, play slowly then make faster! Can you even compose your own piece of music? Maybe record it?
Mr Marshall and Miss McCullough also say about practice makes perfect, and this is so true! It may seem tricky but each time you try it will get easier!
Have fun and check out the links provided!