Oh man, am I ever glad that I’m doing those really stupid beginner projects. Stuff that looks like it would be super easy to do (and probably is for an experienced woodworker) takes me forever to figure out, and then I still get things wrong.
Right now, I’m working on a simple SIMPLE simple box. I measured out my sides, cut them out at 90 degrees, and then went back to put 45 degree bevels on all of the sides. My first attempt, I spent so much time measuring out the cut on the table saw that I forgot to pay attention to which side of my board was facing up as it went across the saw. As a result, I cut bevels on opposing faces of the board (so from a cross section view, it’s a parallellogram). Ugh!
Then, I apparently measured my bevel cut wrong, because when I was done, my board was shy of its original size. How exactly do you measure this out, anyway? When the blade is perpendicular to the table, it’s easy — just use the ruler on your saw’s rails to measure your cut. When the blade is tilted, how do you measure *exactly* where the blade enters the wood? For 45 degree cuts, I figured out that you can just use the pythagorean theorem to figure out how to draw the leg opposite the cut, and that can help a bit. It’s really easy for 45 degree cuts because you just mark at the length the board needs to be, measure back from that by the thickness of the board, and there are the two legs of your right triangle. When the bevel is 45 degrees, those legs are the same length.
So do all the stupid beginner projects you can, and do them with the cheapest wood you can find. You’re going to screw up what looks like the easiest stuff ever. Learn to laugh at yourself. Patience is a virtue. Enjoy.