Step One: Choose coordinating patterned paper and cut to size to fit your alphabet blocks (I purchased a set of 50 at Walmart for $12). Adhere patterned paper to each side of the block using gel medium or decoupage glue. Trim any paper overhang away with scissor blade close to the block edge for a crisp neat finish.
Step Two: Use a sanding block or sand paper to "rough up" the edges of the block and blend the paper into it. Sand the front with the letter to dull the paint finish to match the paper as well. (I used a rough grit sandpaper).
Step Three: Choose an ink or paint to distress and color the block edges and letter front that you just sanded. (I chose an antique gold metallic ink to coordinate with the metallic finish of some of the patterned papers.)
Have fun with it!