perhaps the following might help:
Would = a formal form of "will"
would like to = a formal form of "want to"
I would like to (want to) have more food
I would like to (want to) go but....
It would/will not be the same without you
could = a formal form of "can"
I could/ can read it
I couldn't/ can't read it
should --> Subject + should + Verb = You should study hard (the speaker asked you to study hard)
