Place pecans in a dry skillet over medium heat. Do not add any oil.
Move the nuts around every few seconds. Just slide the pan around and give it a little shake to flip the pecans or use a heat-proof silicone spatula.
As soon as the pecans begin to brown, remove them from the pan onto a plate.
Oven Method
Place pecans on a baking sheet. I like to use parchment because it makes removing them easy.
Put the baking sheet in a preheated 350° oven for 6-10 minutes, flipping halfway through cooking.
As soon as the pecans are fragrant, remove them from the oven and place them on a clean plate
Notes
Always stay near your pecans while they are toasting. They can go from nothing to burnt in no time at all.
Actual time will vary depending on your stove, your pan, your oven, and the amount of pecans you are toasting.
Rely on your nose, instead of the timer. You'll begin to smell the nuts as they begin to brown.
Remove the pecans from the pan or baking sheet as soon as they are the desired color. Otherwise, they will continue to brown in the hot pan.
Roasting in the oven creates a more even browning.
Small black marks may appear on the pecans when roasting in the pan. These are not burnt, however, if they stay on the heat any longer, they will begin to burn. You'll be able to smell and taste the burning. Try not to let them go that long!