17, 101 lbs, F.
A lot of people here have suggested developing good habits (sleep, exercise, healthy eating) as the best nootropic, with herbal supplements as being the next step, and having done both I really like the way my life has improved. I feel much more relaxed on a daily basis, and I'm more productive on busy nights because I don't procrastinate out of anxiety. All of this works out for me, so I don't think I'll be trying anything stronger until I'm older.
Daily stack:
Caffeine (strong black tea) + l-theanine: 1 mug/100mg
I used to be extremely sensitive to caffeine - couldn't drink the stuff, even in the morning, without guaranteeing jitters and a sleepless night. Pairing this with theanine has been a godsend.
This combo makes me feel alert, focused, and stress-free. I hardly ever fall asleep in class now, partly because I'm getting closer to 8 hrs of sleep a day, and partly because of the caffeine. It particularly helps with anything logic-related such as math or programming. Doesn't help with memory, though. I'm looking into getting my hands on some bacopa.
Insomnia stack:
Melatonin + l-theanine: 0.5mg/200mg
Melatonin causes spotting and irregular periods for me, so I use this sparingly. (Don't know what the male equivalent is, but I definitely suspect it messes with your hormones.)
On days when I absolutely need to get to sleep earlier (night before interview, competition, etc.), though, this is a necessity.
I fall asleep within the hour but I always wake up within 6 hours - perhaps due to the dose being a little too high for me. I always wake up feeling refreshed, despite not sleeping a lot. It's also good for jet lag or "resetting the clock" if I find myself getting to sleep later and later throughout the week. Wouldn't take this for an extended period of time, though.