Look, Cover, Write, Check
This is probably the most common strategy used to learn spellings.
Look: first look at the whole word carefully and if there is one part of the word that is difficult, look at that part in more detail.
Say: say the word as you look at it, using different ways of pronouncing it if that will make it more memorable.
Cover: cover the word.
Write: write the word from memory, saying the word as you do so.
Check: Have you got it right? If yes, try writing it again and again! If not, start again – look, say, cover, write, check.