One of the best artist techniques I can pass along to fellow inkers is simply watch your outermost lines they should be thicker than your inner lines. many artists use this technique also try tapering your lines it gives female characters a more fluid look as far as coloring goes try an additional shade for your colors it helps allot. These are just techniques and I would never put down anyone's art your piece already stands out as a really nice pic. These additional techniques may not suit you, if so just ignore them.