Cover the surface with paper or some other suitable material, like a plastic tablecloth, to protect the area from getting stained. You might want to wear rubber gloves, too. You'll also need:  One container for each dye Warm or hot water Plastic bags (if immersing) The more dye that you add, the more saturated the color will be (and the less water you use, too). Light wood works the best with food coloring as it takes on color much more easily.  Mix it up well – food coloring has a tendency to take a while to dissolve if it isn't given a push in the right direction. The darker (and bigger) the wood and the more water you have, the more dye you will need. Be prepared to clean out your stock in your kitchen for the craft. A resealable plastic bag is ideal for immersing the wood, depending on how large the piece of wood is. If it is really large, use a plastic tub. You can also use a foam brush to apply the dye. This makes it easier to control and is better for smaller objects that have nooks and crannies. It does take a bit more patience, however. The longer it sits, the more saturated the color will be. Want it bright and vibrant? Leave it in, go watch an episode of your favorite TV show, and then come back and check on it.  If you're using the brush-on method, you'll probably need at least 3 or 4 coats to get a significant color. Apply the first coat around the entire object before you move onto the 2nd to ensure an even look. Keep in mind that the color will lighten as it dries. Use paper towels or some other surface you're okay staining. Leave at least overnight, and check in the morning. If it's gotten too light, you can simply apply another coat or two. If you're happy with the color, considering sealing it in by spraying the surface with a polyurethane spray. You can also take a brush to spread it on. This adds a varnish or shine to the object in addition to providing a seal against general wear and tear.
Prepare a workspace. Place a few drops of dye in a suitable container full of warm/hot water. Place the wood in the water-dye mixture. If immersing the entire piece, let it sit in the dye for 10 minutes or so. When finished, let the wood dry.