Practice or Practise

The sentence is incorrect and should end with 'practice', in American and British English. Outside North America, practice is a noun; practise is a verb. In US English, the verb and noun are both spelt 'practice'.

I don't know **** about proper English but am pretty sure it is practice.

In this context, it (practice) is used a noun. As such it is a clearly a British context following their rule and spelling.

That being said, for future reference, as a British-ism, practice is the noun, practise is the verb. In American English that spelling, practise is never done, as only one spelling exists. It can be either noun or verb.

http://www.grammar-monster.com/easily_confused/practice_practise.htm

By the way, there's nothing wrong in either language, American or British English, with ending a sentence with a verb. Within the context which you're asking, it happens to be used as a noun.

It is very common. Thou shalt not kill. Glass is easy to break. Paper is easy to burn. I saw the horse jump. I never heard my mother curse.

The last of the above is not actually true.

Good point, these are clear examples where a verb comes at the end of the sentence.

Many thanks for clarifying this point.