When we want to advise someone or want someone to do something in a particular situation we can use had better.
1.Had better is always in the past form ( have better is impossible )
You had better go
Not you have better go
2.After had better we use the infinitive without to
Don’t be upset: You had better try again.
Not had better try
Feel bored: I had a better watch movie.
Not to watch or watching.
You had better finish the homework
He had better talk to her again about the matter.
Had better not + infinitive without to
You had better not go shopping.