>>15777332It's kind of hard to give useful advice without being able to see your design. Generally it helps to give your colours some sort of hierarchical relationship, such as 2 main colours and 1 accent colour (like in picrel where black and white are the main colours and blue is the accent). Or else if you have 2 similar colours (say, 2 light colours and 1 dark colour), keep the light colours grouped together.
Also think about parts of the jacket where it might be natural to have colour changes - sleeves, pockets, straps, zippers, drawstrings, the lining, etc
Also don't worry about being too similar to an existing design. It's unlikely that anyone will notice and if anyone does they probably won't care.