Before you cut a board, you need to do 2 things:
1. Make sure you are measuring & marking the boards as accurately as possible before you turn on a machine.
2. Be safe in all that you do.
At the top is a T-square with engraved measurements, from Woodpeckers. Great special purpose tool. The Starrett combination square below it is much more functional, and is always the first tool I grab to mark and measure new stock. The 6″ and 12″ steel rules are also shop essentials. Two pencils here: the one on the left is always at the table saw, and was made for me by my brother-in-law. The one on the right uses smaller lead, and is more accurate for layouts.
So many tools here! Triangles, a square, a combination square … a pencil.
A compass lets you draw a circle; this one has an extension arm allowing circles up to 12″ in diameter to be marked.
You need 2 identical tape measures: one lives on the table saw, and the other is at the work site.
SAFETY. I always use safety goggles and a push stick on the table saw. Always. Hearing protection is required with a planer or jointer; some use it with a router or table saw as well.