Momma, here is another easy coaching practice more for you than for her. If she says for instance “that chair would look much better under the window” which of course to you seems like a criticism and that you can’t do anything right…. try saying “do you really think so? I guess I can try it and see if I like it that way. I can always put it back if I don’t.” In that way you validate her opinion which she is entitled to whether it is appropriate for her to say it or not; and you can hear her out without feeling that she is criticizing you rather than voicing an opinion. You can then try it out and see if she actually has a good eye where furniture is concerned and see if you like it that way or not, you never know you might learn to value her opinion. If you don’t you put it back and the next time you can say “mom, it tried putting the chair the way you suggested, I understood why you said it, but I prefer it this way. I appreciate that you tried to help though.
In this way, you are not ignoring her comments, not getting hurt by her comments, showing her that you respect her and hear her and yet showing her that the choices are still yours to make.
In a different scenario where she would comment on your cooking or cleaning you can say “I hear that, so how did you manage to impress YOUR MIL with your cooking and cleaning while raising your family? As you know it is not so easy while raising small kids. What were your tricks when your kids were young and you were expecting your in-laws over? Is there anything you can share with me?”