A Drill press – works every time! But if you don’t have one there is an easy jig you can make to handle right angles. Just drill through two pieces of 1/4″ hardboard, than separate them with a scrap piece of 1 X. Line the holes up and tack the hardboard to the 1X and you’ve got a jig. Clamp it to the board you need to drill. You can do the same thing for other angles, it just takes a little more effort.