My mother-in-law keeps on critising me. how do I tell her politely to not do that?

I know how you feel, I get it alot from my partner's mother these days to a point where I'd avoid her if I can. But I can't so I just let it through one ear and let it out the other. Let live and let go. I know it is hard especially if you hear it every day but if you do not dare tell her off, best to just shake it off and just focus on the positives. Take it as constructive criticism or charity haha.