Wah How to use "Had better"

You can use had better or had better not to give suggestion or advice to someone.

Had better + verb

I had better go now. I had better to go now is incorrect.

1. Had better is similar to should but we use had better for giving strong advice which is quite serious if you do not follow it.

    You had better study hard for this examination. 

    (You should study hard for this examination.)

    You’d better go to bed right now if you don’t want to be drowsy tomorrow.    
    (You ought to go to bed right now)

2. You can also use had better when you think it is a good idea to do something.

    You’d better not to be late in English class. 

    (It’s not a good idea to be late.)

    The traffic is very bad today; we’d better go to the Wasabi Park by train.

    Hadn't we better be at the Central Park now, John have been waiting for us.