Set your learning onto one topic at a time and focus on that.
Make the learning as simple as possible- simplify your language and note down the information clearly in lists and small sentences.
Keep control of your focus- don't procrastinate and sit in a calm area to take in maximum information, music and TV aren't really beneficial as background noise and neither are screaming children.
Scan reading (or skim reading) is a beneficial technique to master when learning, developing this talent means you can pick out key parts of texts and digest these easier.
Test yourself regularly, or get people to test you on the subject. It's very beneficial because hearing people say things or writing them down makes information go in easier, at least for me. Testing yourself also shows you your weaker points and how to improve on them.
Never assume that you know something after reading it once or twice, always re-read notes and pages if you're struggling to remember things.

If you get tired or bored stop, walk away and return when your replenished and more awake. Down lull the sleepiness with energy drinks because the stuff won't go in very well. If it's becoming too much for you, just stop for the day, or at least for an hour or two.
Copying up isn't beneficial as you won't be paying attention while you're doing it and all the information will fly over your head.
Keep your notes organised because if your books, notes, tests and writing are all over the place it's likely the information in your brain will be as well.

Similarly, don't panic. I find it very disruptive when your mind tells you that you won't be able to to do and puts in motion a feeling or stress and worry which will tamper with your studies.
Be curious- ask questions and do some research if your struggling to grasp a concept or want to know more, use the internet and sites like Quora to your advantage.
Come up with revision techniques and times to do your work that suit your in your lifestyle, make time for studies but don't force it to interfere with your lifestyle. Revision techniques are a must and you should find ones which suit you (i.e. Games, quizzes, reading over and over, putting post-it notes round your house with information on, etc...)
Linking back to other points, monitor your time by not spending too long on your work each day- just a couple of hours every week (or some more if you feel it to be necessary). Also, do not cram your studies into one night before the test or a day you have free, it won't work as much.