This is the process I follow to make characters most of the time. These images are from a piece I made several years ago. My process has mostly not changed, but I can complete a character in about a day now where I used to take a week. I've got experience with lots of different 3D modelling and texture painting software. I have recently switched from mainly using 3D Studio Max to Blender.
I'll usually start with pencil sketches, but sometimes I can work out anything I'm not sure about jumping right to a 3D sketch. I'll create a sculpture quickly. I try to get large scale anatomy right before proceeding. Surface detail and the density of the model don't matter at this point. This sculpture is 300,000 polygons.
Next I trace a low-poly mesh over the high-poly sculpture. This mesh is 1600 polygons.
At this point, depending on the result I am going for, I might block in vertex colours and proceed to rigging for animation. Vertex colours can be baked to a texture later to reduce the work of painting one. If I'm trying to capture a high detail look, I'll unwrap now and bake detail from the sculpture into a texture and normal map.
I'll refine and add detail to the high-poly model at this point. Colour and surface detail can be painted in as well and baked into another set of textures.
You can also follow this process in the time lapse videos I've recorded for other models.