have to means to need to, or to be forced to, or must. There is no way that you can escape doing this thing.
I have to renew my visa next week.
I have to get a birthday present for my wife.
I have to work late tonight.
should is used to say or ask what is the correct or best thing to do. This is the best way of politely offering advice.
You should try the mango ice cream, it's delicious!
You should always cover your mouth before you sneeze.
You should look at the context.
you had better is what parents say to children: it implies that you think the person doesn't want to do it, and hints that something bad will happen if they don't do it.
You had better get up now, or you will be late for school!
You had better clean this mess up, or you won't get any ice cream.
You had better pay attention, or you will fail the exam!
In the example that you quoted in your comments, it is essential to look at the context in order to tell the difference between fruit and result, so
You have to/need to/must look at the context.