One very important task that is constant during the sculpture process is critiquing your work. Be honest with yourself from early on in the process and dont be afraid to change things up or start over from scratch. If the piece you currently have in front of you doesn't have the correct structure or form it wont matter how long you take on the details and features, the piece wont be as strong. I have had a couple pieces that in the past i created life size busts but after 1-2 hrs in the shapes didn't seem right. It was easier for me to pull the clay and restart rather than try to figure out and fix the problem areas, and the pieces turned out better when i had a fresh new piece in front of me.
The picture above is some of my mini-busts i have set aside that i like. In this case i do studies everyday to get warmed up and work on my techniques in this smaller scale. The ones i like i will work on further, but with me doing new pieces every week i have to judge each piece to make sure it makes the cut and is strong enough for me to spend my time and money on to complete the sculpt and make the mold.
So always remember to critique your own work with an open and honest mind. If the piece your working on doesn't give you a chill of excitement down your spine then somethings wrong.
Figure out what it is and fix it or start fresh.