This is my first instructable, but im going to show you how to make drop through cut outs in your longboard deck. Im using Randal RII series truck. If you don't know the difference between drop though mount and top mount, top mount is where the board is mounted on top of the trucks, and drop though is where the deck is mounted on the bottom of the truck, and the truck goes through the deck. The benefits to drop mount are that it makes pushing easier because you aren't as high off the ground. Also it makes for a lower center of gravity.
Step 1: Draw the cut out
I have Randal II trucks and on their website you can download a PDF file of the template for the drop through cut out.
The first step is to print out the template and cut out the cut out section, align the holes with the holes on your deck, then draw the template on the deck. I held the template in place by putting the bolts through the template and the deck.