Layout is the most important step. Lots of ways to make those lines even if you are not handy with a v-chisel (veiner). On a cheekpiece, lay out the line, start the groove with a backsaw, coping saw or even a hacksaw and use a sharp triangular file to clean it up. On the lower edge of a buttstock, you need to decide whether or not the line will be parallel to the lower edge or start wide and come closer to the lower edge near the trigger guard. If parallel, use a marking gauge to scribe the line. It's also easy to use a pencil held near the tip and run it using your knuckle along the underside of the stock to hold the tip a fixed distance from the edge. If you want to fade it, then some folks can do the same technique with a pencil by changing the angle as they go along. Once it's layed out, you can work with a checkering tool if you're not good with the veiner. If you are good with the veiner, by all means use that and just clean it up with a checkering tool or a triangular file with the handle bent up.