[Christ]

#1 -it makes more sense to accelerate with the engine at peak bsfc.
#2 -it makes more sense to accelerate smoothly in the highest gear without lugging the engine, under as much load as possible.Ee
#3 -remaining aware of your situation and using good judgement will tell you which method to use and when.

Most generally, I use first gear to get moving, nothing else. Once the speedo needle has moved, I shift into 2nd gear and begin accelerating. When I reach a speed in a gear that puts me at idle in the next gear, I shift. I do this audibly because I dont have a tachometer in my car.

In the smooth shifting arena, I'm a king. Often, people riding in the vehicle with me don't know that I've changed gears at all, except by seeing the movements inside the vehicle cabin. Up or down, I match vehicle speed to engine speed before engaging the clutch, IF I actually disengage the clutch to begin with...I often do not.

EDITED FOR CLARITY...