First using the compass and pencil draw a nice, neat round circle.
Step2
Then add in lots of lines going diagonally. Try to make sure they're more or less the same width as each other but if they're not don't worry, it'll just make the disco ball look kookier!
Step3
Between all of the diagonal lines add lines that start at a 45 degree angle towards the outer edges of the circle but become less steep towards the centre of it. On strip in through the diameter the lines should be straight down. This will give the circle a tiled sphere affect giving you your disco ball!
Step4
For an added glimmering, shinning affect try adding stars poking out from the edges of the ball!