I recently learned about a new carving technique from a blog I follow. Its called "Kolrosing." With it you can basically tattoo wood. It is similar to "Scrimshaw" except scrimshaw is the carving of antler and bone, and kolrosing is carving of wood.
To start you draw a design on a piece of wood. I recommend using pencil because its the easiest to remove. After drawing your design with pencil, trace your design with a sharp knife. Ive heard that an xacto knife does a good job at this. I just use a sharp pocket knife or a Mora 120.
Once you have followed your design with your knife you want to fill it in. Ive heard originally it was done with done with powdered inner bark. You can use coffee or cinnamon instead. just sprinkle some over your design and rub it in with your finger. Then drop a few drops of oil on it. Lightly spread the oil over the design with your finger. Let the oil dry, Once dry lightly sand with fine grit sandpaper. The oil sets the cinnamon or coffee permanently into the grooves.
Here are a few I have done
You will more than likely slip a few times while carving your design. This will leave a line where you dont want it. Dont worry about it, start with scrap pieces of wood that way you dont mess up a nice carving. With practice you will get better.
Here is the link to the site where I learned about Kolrosing.
Be safe, always have a first aid kit handy while working with knives.
Most important Have Fun