Step 1: Design
Anyway, you need to draw it out on something sturdy to actual size after you have made a final design decision. I used a piece of wood, cardboard would work. Then you need to decide what your measurements will be. Just saying it right now, simple is safe. I used measurements in increments of 1 half inch. That is to say that I never made a measurement that was not a multiple of 1/2. This helped out a ton when making the frame.
Step 2: Frame it
If you have dimensioned your design, it should be fairly easy to determine the length of rod you need to make one, flat piece of frame. Just add up all of the measurements.
What your going to need to do now is take a pair of pliers and bend that length of rod at every corner of your design, don't bend it to the perfect shape yet or it will be hard to match exactly. Make two of these wire frames then bend them the rest of the way until they are perfectly identical.