I used a medium weight cotton canvas, it's about $11 per yard and I used less than half a yard.
A zipper, the one I used was water resistant and 30" long.
2" wide Velcro, about 18" of it.
White micro-crystalline wax similar to this, purchased at local art supply store. Beeswax or Paraffin would also probably work fine.
Sewing tools(sewing machine, scissors, etc.)
Heat gun, for melting the wax. $15 at Harbor Freight.
Disposable bristle brush, for applying wax.
A heat resistant bowl you won't mind ruining, for melting the wax.
A putty knife or butter knife, for working with the wax.
Step 1: Make a Pattern
Then mark the angle of the front and back, make sure you mark which way is front.
You should also mark where any cable fixtures are so you don't put the velcro straps there.
Step 2: Cut Fabric
Measure the circumference of the piece you cut out, this is how long you want the center strip to be but cut it a bit longer.
I used a 2'' wide ruler to lay out the center strip but you can have more room by making it wider. Just don't make it too wide or your knees will rub on it!