So here is my tutorial to make this very easy Shelf made from old Skies.
Step 1: Get Your Stuff
To make this Ski-Shelf, you just have to get some screws, Brackets and of course some Skies. In the best case take old ones, because they are flatter and linear.
Drill some holes in it, fix all of it and mount it on the wall. Finish in 1. Step