Here are some techniques for needle-felting fabric with felt cutouts, roving, and yarn (100 percent wool materials work best). 

Place a felting-needle mat under the fabric, and punch up and down using a single felting needle or a multineedle tool. A larger mat minimizes repositioning. 

Clean out wool fibers as they collect. Both sides of felted fabric are attractive, so test on a swatch to see which you like best. The design on the punched side is sharp; the reverse is blurred. Take your time, and be careful as you work.