Hey there! Such a cool illustration so far! Keep in mind that leather has strong and clear specular highlights, with some smooth transitions along the folds. You could also use a slightly textured brush to add that subtle “noisy” texture of leather and prevent it from looking too much like latex. And just like with any material, remember that some surfaces can be slightly reflective, so adding a bit of bounced color from the background could work really well here. :) Hope this helps!

