This minecraft glass look is easy and really cheap. You just need a good eye and a little patience.
Step 1: Supplies
vinyl tape / white electrical tape ---- I would get at least 100'
Utility knife - Use Caution!
Measuring Stick (optional)
Step 2: Lines
I did this design on a a sliding glass patio door. It was 8' x 6'
First, clean your glass.
With your white tape mark out a grid pattern. I started with one strip down the middle of each pane and then made the horizontal lines.
If you want you can calculate the exact middles and try to get equal squares. The tape is so easy to use I just eyeballed it.
If your patio door goes to the outdoors, I would put the tape on the inside. Just FYI it will leave a little residue when removed. Nothing a little windex can't take care of though.
Step 3: Slice It
Get a good picture of the minecraft glass pattern.
(the one pictured is from Minecraft wiki. )
Start by cutting sections of the grid pattern and try to cut away the same pieces for each "block" of glass.
Put light pressure on the knife. You shouldn't scratch your glass if you take it easy.
Then peel away squares.
Step 4: Diagonals
You can use already cut squares or cut new squares and line up in diagonal patterns to make the little reflective bits on the glass "blocks"