Once fairly happy with the overall shape its time to start to smooth, this is still done with fingers and then using modelling tools (I used tools purchased from 'Alec Tirantis' based down in Reading, in particular from the BM series and a few of their stainless steel loop tools).
Its hard to actually explain how you use the sculptural tools without watching someone or a video tutorial but another simple way of describing is to roll sausages for things like creases which are not the easiest part of the model to make, I guess if your interested in doing some sculpture theres no better way than just buying and trying !