sould and would are modal auxiliaries (not full verbs)!
you use SHOULD:
-when you talk about an obligation: you give an advice or a recommendation:
You should see the doctor. (advice)
- when you want to claim s.th.:
He should be put in prison.
- if you want to express that s.th is likely to happen:
They should be in Paris by now.
you use WOULD :
- for the conditional clause: If i were you I would go to the party.
- to express a demand (very polite): Would you please open the door?
- for a typical behaviour of s.o in the past: Mary would phone me every day.
- for an offer: Would you like a cup of coffee?
I hope I could help you a bit! *greetings*