What is the key to success in creating a piece of furniture with form?

[swhetten]

What is the key to success in creating a piece of furniture with form? I am able to do a wireframe model starting in plan view and then I can apply surfaces to it. Even if I create arches for a path and then do a ruled surface, I am left with a gap between the flat edge of the furniture and the curve of the surface. This results in a very boxy, uncomfortable chair. How do you add the softness without the gaps? Also, why would you use one surface over another? I am changing locations so I will be logged out for an hour but back on then.
Thank you for your help!

[jaberwok]

Since no-one else has answered, I'll try.
I once drew a pillow.
I made it a solid by drawing three curved shapes - 1 in plan, 1 from front, 1 from left - extruding them so that they all crossed a common volume of space then using the Intersect command to keep only the common volume. I then applied a fillet to all the edges.

HTH