Frank..thankyou mate,hope this gives you the push to start in figure sculpting,i can honestly say that looking at others doing it was the inspiration that got me started.
Nick..Sounds like you are on the way already,everyone has to start with their first figure and mine was a disaster also.The thing to rememer is always learn form each one.I have found that it isnt encouragement that helped me(although this is nice)it is the constructive criticism that really helped from others who could sculpt.
I would strongly suggest doing some figure conversion work,simply pose changes,arms, legs etc before sculpting a full figure as this will help you get used to working with the putty and help you maintain proportions.
as for your questions
#1..i normally make the torso from milliput but in this case because of the ammount of figures i used the torso from some DML figures,just carve back all the detail work then apply putty over this.
#2..i also started out using Milliput but found it very difficult to use,especially blending fresh onto set putty.The stuff i use now is Magicsculpt which i order through El Greco miniatures in the U.K.This stuff is far superior and will make sculpting a lot easier,i still use milliput but only for making the torsos and bulking out the figure.
#3..The fine details are probably the hardest part to do along with proportions,it is a case of practise,its far easier to have a commercial piece from a kit at hand to check size against as you progress.
If you need any help drop into Historicus Formas sculpting section and i will be glad to help as will others.
http://www.elgrecominiatures.co.uk/ Steve