Just practice a softer delivery. Instead of saying "I don't like how this is..." or "This sucks because..." say: "This is good and it would be even better if ..

Just practice a softer delivery. Instead of saying "I don't like how this is..." or "This sucks because..." say: "This is good and it would be even better if ...". This way you're not saying anything negative at all, but at the same time voicing the things you believe should be improved.