Anyone can learn the mechanics of good sketch technique and it begins with setting yourself up to a way of approaching every sketch. Here are my top ten to achieving confidence in sketching.
Understand your forms
Get into the habit of creating section lines so that you are fully aware of the shapes and volumes
Start with a ground plane
Helps anchor the cubes, cones, cylinders and spheres that make up any design
Draw everything simultaneously
Get an idea of the full picture of what you are trying to sketch
Emphasize depth of volumes
Use light and shadow to create the illusion of depth in your sketch
Build in layers
Block out core surfaces with highlights and shadows
Find a focal point
Be decisive and pick an area to detail and leave the rest to history
Practice indicating and not detailing
Detail out what you want to show and indicate others
Be mindful of composition
Support your sketches with other sketches to engage your audience