First of, nice character here. You did a really nice job on the figure and proportions. One idea would be to just expand on what you already started with a few more values. I went with a little red leather feel, but you could just as well take it in another direction. I hope this gives you some ideas on how you might add some simple effects to give the illusion of detail. This same principle can be used on the skin with two slightly darker values from what you have and then one lighter for highlights. Hope this helps.