Our Linden Masters have not made it easy to get an Avatar shape that really looks real. Your Typist’s eyes often know the difference, even if you cannot say exactly what is wrong with the figure or shape.
Penny Patton is the expert. Take a peek at the complexity, suggestions, and pointers to free shapes (MarketPlace SL) you can trust to be correct. It always helps to start from something correct in order to get something unique.