Tools

Tools, ah tools. Starting clockwise from the top and going to the center:

80 and 120 grit sandpaper. These are rolls of sandpaper with pressure sensitive adhesive on the back. Great stuff – roll it out on your kitchen counter, press it down, and you have an instantly flat sanding surface.
A tri-square for marking parts and making sure they’re aligned properly.
F-clamps – you’ll need four.
An electric drill for driving screws and drilling pilot holes.
A good quality glue – Shown is TiteBond II but you’ll also need 5 minute epoxy and optionally marine epoxy.
A sharp saw, a few deck screws, a bit to drill pilot holes for the screws and another slightly larger one (not shown) to drill the countersink for the screw heads, and a curved rasp.