I've modified free plans from http://www.foamyfactory.com/ for a faster build that is also stronger.
This requires just 1 foam core board that can be purchased from a craft store.
I used the 1/2" thick board instead of the more common 3/16" version I've used in the past.
Step 1: Airframe Layout
Put the design on poster board so you can easily trace out the design for future builds.
I've found that making just the vertical profile of the fuselage, the whole wing and the tail is all you need.
Trace out the designs on the foam board.
Step 2: Cut it out
Step 3: Making the wing control surfaces
Using the jig saw cut both ailerons at a 30-45 degree angle where the control surface meets the wing. To make the hinge, mate the control surface to the main wing body at the cut angle and apply the tape along the length. Then fold the control surface the other direction and tape under side of the wing and aileron.
Next, slide the wing through the slot in the airframe. Apply glue to the center of the wing and slide in place. Allow the glue to dry then repeat the taping procedure on the other side of the wing.