Is used when asking for something.
Is used when someone does something for you or gives you something. Ta and cheers can be also used in UK. When you are really pleased, you can say thank you very much.
Is used when you respond to thank you. You can also use my pleasure (you were happy to do it) or don't mention it (informal).
Pardon me - used if you bump into someone.
Excuse me - these can be used if you bump into someone, need to get someone's attention or want to ask for information.
I'm sorry to / bother you - is only used when you want to ask for informatio more polite.
I'm sorry - used when you have made a mistake.
Bless you - polite expression used after someone sneezes.
Cheers - when making a toast.
My condolences - used with somebody who has suffered a death in family.