Party invitation cards

How do you create party invitation cards which are really appealing to people? How should you design them so people say "Yes, I´d like to go to the party!" First of all it is really important that the party invitation card is interesting for people. Not a card which will be put into the bin at once. A party invitation card people look at and say "Well, that´s a nice one!" A party invitation can be really colourful and extraordinary. So you have to reflect what kind of party it should be. Is it a party for children, maybe a birthday party, or is it a celebration for grownups. There can be parties for every season and holiday. A Christmas party is totally different from a mid-summer party. This should be visible in you party invitation in a very special and thought-out way. There should be an eyecatcher at the party invitation card so people can see at once what kind of party it will be. Maybe it is a wedding party then there can be a picture of the rings or flowers. Or it is an anniversary, then you can put a picture of the number of years celebrated on it in a concise way. There should not be too much disorder on the card - rather one big eyecatcher. Inside the party invitation card there should be all date which are neccessary for people who will go to the party: the location, the time and if they shall bring presents or not.