I know this sounds overly simplistic, but it is really true.

(1) Think of something that causes you problems in your daily life.

(2) Does this problem happen to people other than you? If YES, go on to step three, if NO then go back to step one. In order to have an invention that you will eventually earn profit from, you must solve a problem for more than one person. If you just like to invent things that solve your own problems, then please feel free to continue to step three.

(3) Solve the problem in the Simplest way possible. There's an old addage that says if you add extra steps to a process, people won't buy your invention regardless of how great the outcome is.

(4) Write down any preliminary designs or ideas you may have about the design. What will it be constructed of? Is there more than one piece to it? Write down everything pertinent within your inventor's notebook.

(5) Mentally engineer the complete apparatus. Make the invention work in your mind completely. Go through each function of it individually, and make them work properly. Finally put all the pieces together in your mind. Does it work? If YES, then GREAT! Move onto the next step, Patent Searching your invention. If NO, well go back to step three, and try again. Back to the drawing board so they say.