Everything can be broken up in basic shapes: lines, circles, triangular, rectangular.
Devices. Draw devices ... They are only a bunch of lines :)
People. Assemble basic shapes and tweak them to draw people.
Hands on devices. Start drawing simple, there is a lot you can do using only basic shapes.
To draw text start with basic lines and get the line as thick as you need!
One last thing: start simple... Most of the time you don't need more than a few lines :)
Once you have created the outline you can get fancy with the clothes.