This is one that I always get caught on.
Practise is a verb.
Please practise every day.
I am practising regularly.
But I practised today already!
I have been practising for four hours.
The orchestra practises on Tuesdays.
Practice is a noun.
Practice makes perfect.
Please do your piano practice.
With practice, you will improve.
Try using your scales as a warm-up practice.