Now that you have all the lines you need it’s time to start cutting some wood. The most crucial part to get right is the shoulder on the tenon side. This is what you are going to see when the piece is finished and you want a crisp 90 degree edge for the best result. There are many different ways to cut a mortise and tenon but I have found that the fastest and most consistent way is to cut the shoulder on a sliding table saw.
The other thing to keep in mind is to first cut the tenon a little bit oversized and then come back to finnes the fit with a chisel or hand plane to get that snug fit we always strive for.