I am a PhD student and a weight lifter,therefore my fatigue levels can get petty high sometimes.I'll list few things which might help;
1)healthy carbs-fibre breakfast
2)meals every 3-4 hours (350-400 kcal each meal) with less of saturated fats(as most of the times greasy food makes you snooze) and starvation/skipping meals is worst!!
3)green tea helps alot,its natural and thermogenic.
4)8hours of sleep every day (some people require 9hrs-plan your day accordingly)
5)go gym or any activity after studies.will keep you motivated all times
6)sleep early-wake up early (11-7?...burning mid night oil has its disadvantages)
7)having a power nap after lunch for 30-40min is not a bad idea..i do it all the time
8)DO NOT DRINK energy liquids...it mite keep u awake for an hour or two and then you'll be back to square 1.
9)leave the wordy literature for periods when u r most alert...reading heavy stuff after lunch or late evenings is never a good idea
10)get your vision tested regularly
good luck!:-)