Lose and loose are commonly misspelled. There are often mispronounced, too, so maybe this will help:
The ‘s’ in lose (a verb) is pronounced with a /z/ sound. Lose means that you have misplaced something. Example: Where did you lose your keys? If I knew where I lost them, I would still have them!
The ‘s’ in loose (an adjective) is pronounced with a /s/ sound. Loose means the opposite of tight. Example: I have to tie my shoe because my shoestrings are loose.