My starting point is my sketch book. This is my ideas pool where I doodle, play around with variations on themes, or paste in inspiring photos and reference pictures.
Then, if an image grabs me I'll work out a rough 3D model in clay or balsa wood.

For small pieces its easy to transfer an outline of the main view onto a wood block then cut it out with a jigsaw, giving you something like a giant jellybaby. Then, you pick up your knife and gouges and turn your jellybaby into a reclining nude, or whatever.
 
 

The bigger logs are roughed out with a chainsaw and a 1½" no.5 gouge. Further shaping is done with an angle grinder and a large rasp before I pick up my knife, gouges and rifflers for more detailed shaping.
 
 

Small carvings can be held steady in a vice, but larger pieces need to be steadied with sandbags or "bench dogs" - pegs that go through the bench top.
For detail work I find it more natural to hold the piece in one hand and rotate it as I work with the other. Yep, I've still got ten fingers.
 
 

Usually I get fired up by something in my sketch book then go find a piece of wood with the right dimensions. But... sometimes you come across such an odd shaped log that you have to play with ideas until you get something that will fit the wood.

This particular bit of storm damage sat in my shed for months, sparking no ideas at all. Then, when I was stripping the bark of it, I turned it upside down and suddenly the ideas came. This odd shape eventually became Sitting in the wind (see Gallery 2).