I want to share a way to accurately mark a dowel joint. I used this technique recently to join the legs and top of the dog bowl stand. It’s a simple method. Place a small nail on one piece (here the leg), then position the other piece where it needs to be and press together. This will leave an indention caused by the nail head on both pieces in the same spot. Center your drill bit on this indention (as shown below using brace and bit) and drill to depth. Next, simply place the dowel in the leg and press the top down onto it.
I use tape on the bit to mark the depth I need to go.