If the stool is not store bought, prep it. Sand the surface so that it is smooth and even.
Pick the colors you will use to paint the stool. One of the colors will need to be dark brown. Use the dark brown on the areas of the stool you want the color to show through (corners, the legs, etc.).
Apply petroleum jelly with your finger or a q-tip to the parts of the stool that you want to look aged. Spread it so that it is smooth. You will be able to find these areas later; the paint will look shiny and crackle a bit.
Paint the entire stool.
Once the paint is dry, take your fingernail and scratch away at the areas the petroleum jelly was applied. The paint will come away fairly easily.
Create your monogram on a program like Microsoft Word. Use a large size, 200 or larger, and choose a font you like. Once you print the monogram, cut it out and tape it to the carbon paper.
Place the carbon paper onto the stool and center it. Using a ballpoint pen, trace over the monogram several times. The stenciling should be dark and clearly visible on the stool.
Paint the stenciled lettering with a very small brush.
Once the paint is dry, lightly rub the sandpaper over the lettering to give it a distressed look.
Enjoy your new creation!