I just wonder what is the best way to teach students suffixes,prefixes
since they make a lot of mistakes by affixing the wrong prefixes/suffixes to root words as in *inkind
I don't think there is necessarily a single best way. They can be confusing and patterns like im- before the letter p are not rules as there are always exceptions. The more they read, the more times they will come across prefixes and suffixes and then they will become more natural to them, in addition to practising them.