This is one of those super easy projects that the most time is spent on it drying...
Go to your local hobby lobby or craft store and buy a blank wooden sign...I bought one that was kind of like a pallet/fence (because I loved the character it had). They always have lots of options at these stores; some of the signs are raw wood, others are already stained or finished. Mine was raw, so I stained it with my left over dark walnut stain from my table. Be sure to let the stain soak in for about 5 minutes and then wipe up any excess stain so there isn't any drippings or stickiness. I wanted my sign to look weathered and worn so I only did one coat of stain..since the wood had different grain patterns on each board, they all took the stain differently and I really liked that effect! Let the stain dry over night or at least for 3-4hours. Cut a stencil in vinyl or buy a stencil from a craft store (I used my Cricuit so I could have the font and size I wanted). I used vinyl so the stencil would stay put for multiple paint applications and so paint wouldn't leak around the edges. When applying paint, use a sponge brush and white acrylic paint. Dapple it on in small random strokes. Be sure you do stroke a little bit and not just go up and down with your brush...you want mini strokes instead of big ones (so they give dimension and are less noticeable, plus it won't matter if they don't match up with the other letters.) Apply a second layer just like the first but don't try to cover every area available. You want it to look worn and imperfect. Let that dry for about an hour.
Now, grab some 220 grit sand paper and roughen up the edges of your sign..I was able to rough up some of the middle pieces of mine too! Then, take the sand paper and lightly sand around the outside and inside edges of the letters...don't make each letter the same, you want random and imperfect. Like it's been stored, dropped and bumped for a lifetime.
Once you've reached the level of wear and tear you like, you're done! Hang it up and enjoy! I know I love mine!