I wouldn't even consider nootropics until you're already getting plenty of sleep, eating well, exercising regularly, and not using too much caffeine or alcohol. Those things have a much bigger impact on your state of mind. Nootropics are attractive in part because they represent the dream of sharpening your focus without all that boring lifestyle stuff.
Piracetam is cheap, studied (at least compared to the rest...), and doesn't have any particularly bad side effects. If you're going to take anything, that might be a better place to start than amphetamines (!) such as adderall. Of course, I'm not a doctor, but I doubt you are, either.
I've had the best results with green tea (which includes l-theanine) and getting enough sleep, FWIW. (Also, meditation helps.)