It depends what kind of stuff she likes, say if it was maybe she likes horses or something, decorate where the party is going to be with horses, and make posters saying miss you so much <3 make a cake saying the date of when shes leaving and her favourite cake flavour (choc etc) write we all miss you, give her cards, balloons, make it really nice for her. There will probably be better answers on google search, if you type in leaving party. I hope my ideas were clear and good enough!

Goodluck on the party :)

Everyone gets up and makes a quick small speech about a story about her.

Have a T-Shirt, hat or Calico bear for everyone to sign.

Put up collages of photos and comments.

Have trivia questions to answer about her.

Set up a photo booth with a few accessories to put on for the photo.

Make a slide show.

My best friend is moving away and me and my mates have decided we want to do a surprise leaving party for her, but we don't kno what to do at it, like we want to make it really memorable but don't have any ideas, any ideas?