Step 1: Tools and Supplies
2) design idea, text or artwork, I laid mine out in Coreldraw but you can use whatever your comfortable with or just draw on the surface
3) paint, I used Sherwin Williams latex acrylics
4) brushes, I used cheap brushes I got in a 25 pack at a big store retailer
5) sandpaper, transfer paper
6) not necessary but I used some crackle medium to help age the paint
Step 2: Coating Out
Coat the board in two contrasting colors, I used black then white. Apply the paint loosely you do not not need or want even or complete coverage, allow some wood to show through. When this is dry to the touch (I used a heat gun) apply your contrasting color I used white because the school colors are blue and white. let this dry to the touch and then take some high tack tape such as duct tape and apply randomly and pull off some of the paint.
I used some McLoskey special effects crackle glaze between these coats. there are similar products available at paint stores and craft stores.
Step 3: Artwork
I then used saral transfer paper to copy my design to the board, I had some red so I used that, graphite paper works as well or flip the pattern over and rub it with a pencil and use that. if you are going to do more than one you might make a pounce pattern.
Step 4: Painting
the final step is using sandpaper and scrapers to carefully scrape away some of the paint revealing the layers underneath,
another technique is to throw it face down in the driveway and rub it around in the gravel a bit (not too much). You can also drive some nails in to it and beat it with a chain. I also sometimes take some muddy brown color thin it out and rub it in to the sign.
Step 5: Finishing Up
This is just one of the ways I go about creating old signs. If you need anything clarified let me know in the comments.