A julienne (also called a "matchstick") is a type of cut that makes a long thin strip. It's a good technique to use for vegetables and other ingredients when you want to heighten their presentation.
Clean your cutting board and knife.
Peel the skin from the vegetable, if necessary.
Trim away any root or stem parts of the vegetable.
If the vegetable is round like a potato or carrot, cut it in half and lay it, cut side down, on the board. This will keep it from rolling.
Cut the edible part of the vegetable into slices about 1/4-inch thick.
Cut the slices into even strips, 1/4-inch thick.