Rule one: make something people want
One of the most prolific inventors in history, Thomas Edison worked largely on the generation and distribution of electricity, contributing towards the invention of the carbon transmitter (and, by extension, the telephone). His inventions would shape the entire 20th Century. He's renowned not only as a great thinker but also as a great businessman – finding a way to make new creations a commercial success.
Try, try, try again
His early career was as a telegraph operator, and consequently many of his early inventions concerned telegraphy. But the invention that first made him famous was the phonograph, an early type of record player that reproduced music recorded on tinfoil cylinders. Over the years, his collection of patents swelled. But for every invention that worked, there were dozens that didn't. He famously said that "I have not failed. I've just found 10,000 ways that won't work."
Incredibly prolific
He would invent (or co-invent) many items we today take for granted, including the incandescent lightbulb, an early version of a motion picture camera, power distribution lines and the fluoroscope – a machine for taking X-rays, the basic design of which is still used today.