I repainted Bumblebee with metallic gold.
Repainted his rockets silver.
Modified his stingers so they would fold all the way into his arms and not stick out.
Make a reproduction of the autobot symbol for his chest.
Made a couple of weapons for him: a shoulder cannon that becomes his muffler in alt mode and a hand held stinger missle launcher.
Painted details all over him to be as accurate to the cartoon as possible and still keep him from looking too simplistic.
I made the shoulder cannon as a weapon and then found that it looked like a custom muffler!