1. to express a polite offer or request:
Would you like tea?
Would you like me to do it?
2.to describe a habitual past action:
Every evening I would walk in the garden.
3.used in speaking of something that will, may or might happen(eg. if a certain condition is met):
If I asked him to the party, would he come?
4.used to express a preference, opinoin etc politely:
I would do it this way.
5. used, said with emphasis, to express annoyance:
I've lost my car-keys-that would happen!
Hope that help you.