Do you use a wireframe or armatures? The mini doesn't look bad at all for a true second try. A good way to do faces is doing them in parts. Start with a small blob, that's what you'll get when starting with prebuilt armatures. Add a chin and cheeks somewhere up to the eyes. Let id dry a bit and add a mouth. This can be done as easy as using a small knife to cut a mouth, pressing it a little into each direction to achive something like lips. Let it dry again. Next add a forehead and or a nose.
Now you'll have a basic face without eyes. That's as far as I got on my second mini. I then added ears, hair a comset and finally mirrorshades, so I have no idea how to sculpt eyes on humanoids. My first mini was a procupinefish-kitten. A mini inspired by the fugu-kitten stuffed animal a friend of mine has... weird idea, weirder mini...
But then again I'm not sure how to classify my attempts. Sure those were my first tries at whole minis, but before I've modifyied minis countless times and tried a lot face sculpting with putty left over from modifying.