Set up the area you will be working on. I like lining the table with newspaper or craft paper.

Wash and dry your potatoes. 

Once the potatoes are dried, add 1-2 potatoes to a zip close baggie.

Then add 2-4 drops of food coloring to the baggie, depending on how bright you want the color to be.

Zip the baggie closed and then shake the baggie gently to get the food coloring on the the potatoe.

Once the potato is colored, remove it from the baggie and gently dab any access food coloring off the potatoe. 

Place the potato on a paper towel to dry.

Repeat with the rest of your potatoes and the colors that you want to use.