Asking people to a party is an art. You must think about what kind of party you're going to have first. If it is a small party, you can just give a call to your friends and ask them to the party. You can even e-mail them or just leave a message for them.
Now, calling someone is an art too. First, give a call to your friend, and then begin the talk by asking them about their life and family. Ask them about their schedules on the day of the party. If they say they are free, you can ask them to the party directly(直接地).If the friend is not free, then ask him to try to find time for your party.
If you're going to have a big party and need to ask lots of people to your party, you must decide how many people you want at your party. Then you can write a list of them and send them beautiful invitation cards, because you may not have so much time to give them a call each. You must send the cards a few days before the party so that they can have enough time to prepare for it.