Hmm... A few, yeah. First, remember that organic things are usually round. Your head, eyes, ears, nostrils, even your fingers: round. Make sure that when you're going from a vertical line to a horizontal line, you round the corner. Check out any post of mine in this thread, and compare my modifications to the former ones.
You should also complete your line art before moving on to coloring or anything like that, but you can always add parts to it later.