Confusion over the use of practice and practise is common. For most varieties of English, practice is the spelling for the noun and practise is the spelling for the verb.
Verb:
I practise every day.
Noun:
It is my practice to write every day.
If it is a thing, use practice. If it is an action, use practise. I find it helpful to link them to advice and advise. Most English speakers instantly know the difference:
Verb:
Iadviceadvise you to stop.
Noun:
I gave you someadviseadvice.
The word with the -ice ending is a noun. The word ending with -ise is a verb. And you can apply that to practice and practise.
In American English, practice is the dominant spelling for the noun and the verb. However, the distinction is sometimes observed.