I use traditional tools and techniques as well as modern technology where it makes sense.
During the design process, I use sketches and scale drawings where beneficial, and I almost always use 3-D mockups to give me a good idea of what the final piece will look like when completed. The mockup allows me to explore ideas, shapes, and sizes to see what they look like in three dimensions. Even scale models or full-scale drawings can only give a close approximation — nothing beats seeing the idea as a full-scale mockup.
Many modern power tools are very useful for the rough work of bringing rough boards down to final dimensions — much easier and quicker than using hand tools! I also use power tools for milling many kinds of joinery.
However, nothing beats a hand plane for creating fine surfaces and details. A finely adjusted spokeshave quickly and easily creates a gentle curve, and a sharp chisel or gouge is indispensibe for fine-tuning joinery to a perfect fit or adding texture to a surface.
Accuracy and fine tolerances on joinery are critical both for the look of a piece as well as its strength and longevity. This is why all of my joints are carefully hand-fit to fine tolerances. Power tools are very useful to getting many kinds of joints very close, but the final fit is done by hand.