There's one extra word in each sentence. Cross it out It might be a good idea to cut out on sugar.
You might be feel better if you go to bed earlier.
If I were you, I would better go on a diet.
I don't know what mango is like, so I'm going to try do it when we visit Thailand.
I have done that yet and it didn't work.
You had better do not drink latte if you are lactose intolerant.
Why don't you book visit a doctor?
I'm not sure that drinking more of water will help