What you'll need:
disco ball-I got mine from Hobby Lobby
serrated knife & metal spoon
small towel or oven mitt
small pot-I got mine from the $ section at Target
large screw & screwdriver
small plant & soil
small piece of aluminum foil
*First, measure the width of your pot so you'll know what size hole to make in the disco ball. I did everything completely backwards, and it took much longer!
Take your pot and drill or screw holes in the bottom. I just screwed a screw in enough to make the holes, then took it out. Omit this step if your pot already has holes. Then add your plant, soil, and water. Let it drain for about an hour. I actually used pieces of a plant I already had.
Take your (pre-measured) disco ball, and start cutting in a circle, in between the mirror tiles. Make sure to go a little deep into the ball to ensure you'll be able to pull the inside out. I held it tightly with a towel with one hand, while I cut with the other. It took me a while to get the shape right, mainly because I didn't MEASURE FIRST!!! But I eventually got there. If it's not deep enough, just take the knife around the inside and scoop more styrofoam out of the middle with a spoon.
Put the piece of foil firmly in the bottom for any minor drops of water. You should still always let the plant drain for at least an hour before putting it back into the disco ball. This will also make it less heavy. Add your plant to the disco ball, and you're done!