Is this a major contest or small con competition? You said you were competing for 2 years now and only did it at the same convention, so you competed 2-3 times and are disappointed for not winning yet? Also if you enter a contest with the sole purpose of winning it will ruin the experience. Every convention should have a rule book and a judging guide on what is weighted at the con. Normally getting creative is not what is asked for, the design should be as close to the original as possible. 1/2