As mentioned, there are numerous ways to make a 'proper' shower that will last leakfree for decades, and many, many more ways to mess up. A few simple, general rules: the waterproof layer must be sloped to the drain - this is NOT the tile, but underneath it; that waterproof layer must extend above the curb height and over the curb (at least a couple of inches); depending on the method you use, you generally should have a vapor barrier behind the wall (some methods put it on top of the wall, which has advantages since less can get damp - thus the shower dries out faster). Wedi is neat stuff, Kerdiboard is similar, hydroban, and numerous other products (my preference is Kerdi, but lots of others work well, too) are available. A 'conventional' shower has a pvc liner and cbu walls with a vapor barrier behind. There are variations on that theme. Then, lots of surface treatments from membranes and paint-on materials. A surface membrane can have drywall as the substrate, but none of the other methods should have any drywall in the mix (unless it is above the showerhead).