Start by picking a couple of colors to use. Pink and white are very popular colors but any color combination that your daughter likes can be used.
Here are two ballerina party invitations that you can print out.

This is a pre-printed fill in invitation.
Just print out the invitation, fold in half and in half again.
Fill in the party information and get ready for the party.

This invitation is a half fold invitation. Print the page and then fold it in half.
The inside of the invitation has been left blank so you can add your own sayings and party information.
You can decorate the party area will tulle or netting. Tie bows to the backs of chairs using 4" or 5" wide strips of netting.
The table can be decorated with a plastic tablecloth and large bows attached to the sides so that the tails of the bow flow almost to the ground.
Balloons and streamers are inexpensive decorations that create a party atmosphere in hardly any time at all. Blow up balloons with helium and let them float through the air. You can also inflate a bunch of balloons and let them drift around on the floor for a magical effect.
Divide the girls into two teams and line them up on one side of the room.
Set one skirt and one set of shoes near the other end of the room.
On the word "Go" the first girl in each line, runs to the pile of clothing and puts on the skirt and the shoes/socks. If using socks, they have to pull them all the way up.
The girls then must twirl a complete circle and take off the clothes and run back to the line and tag the next girl.
The winning team is the one that completes the dressing, twirling and undressing first.
Preparation Before The Party:
Spread the puzzle pieces out on a piece of cardboard with the printed/glossy side facing up. Spray the pieces using several light coats allowing the paint to dry between coats.
Making The Frame
Glue the magnet to top of the frames' backside.
Glue the painted pieces to the cardboard frame.
Place pieces in a single layer, letting the pieces overlap the edges slightly. A second layer and possibly a third layer will be needed to cover it completely.
You can add ballerina stickers or gems to the frames.
Take a group picture, print one out for each girl to put into the frame so they can remember this ballerina theme party for years to come.
ShindigZ.com - the World's Largest Party Superstore
Prima Ballerina Theme Party Supplies
Print it out and trim just outside the black lines. Lay the template on a 9 x 13" sheet cake and trim the cake from around the template. Freezing the cake for an hour will make cutting the lines easier.
You can also keep the cake whole and pipe icing along the edges of the template to give you a ballerina shape to fill in with icing.
Wilton Ballet Shoes Cake Pan would make a nice cake for a ballerina theme party.