You should wear a uniform to school.
- suggestion and advice:
You should see that film, for it's very educational.
If the pain persists, you should see a doctor.
The modal verb would is used to show imaginary or hypothetical situations (especially in conditional sentences):
If I had lots of money, I would go around the world. (but I don't have lots of money)
I think you would be a good football player. (you're not a football player, though)
Bear in mind I'm not a teacher!