Concentration is a very important skill that every possesses, however very few actually practice it. Yes it is a skill in which you can practice and get better in, it isn't the same as self control. It is your ability to essentially not get distracted when a lot of distracting things are around you. Luckily there are a few easy to use techniques which can improve your concentration if you feel like you cannot concentrate enough.
Most of you will love this one. Take regular breaks! You are only human and short breaks to reward yourself for concentrating and actually getting things done is normal and very acceptable. You should not feel bad about taking breaks either. They are essential to not getting burned out and making it exponentially harder to work on something. Also it is important to remember there is a difference between pushing yourself and overworking. You should always push yourself but never overwork.
Tune Out Distractions
You need to develop tunnel vision and tune everything else out. If that means moving your work to another room so you can study, that is fine. If you like to turn on some music so that you can tune everything else out, that is fine as well. Another good thing to do is to recognize distractions before they turn into distractions. What I mean by that is things such as a cell phone, while not horribly distracting all the time, unless you get tons of text messages, it will break you out of the zone. That is why it is probably best to turn things like that off or at least on silent and only check it on your breaks
Focus on One Single Thing
If you are studying for a test you probably have so many things going through your head. Such as needing to get enough sleep, eating a good breakfast, arriving on time. The list goes on, and this is only a test. There are tons of things we worry about when we need to be just focusing on one single thing. While the other stuff is important, it can wait until we take care of this.
Variety is Important
You are not a machine, you need stimulation occasionally. This means picking up a game for a few minutes, taking a small walk, checking your cell phone, anything really. This could and probably should be done on your break if you do any of those things, however sometimes if you are working on a certain task you can start doing something else but related to your goals. This type of transition and not focusing on one thing for an extended period will help you get back on task faster and better than before. No one can spend forever on a single repetitive task without some degradation in performance, it is just how we are wired I suppose.
Push Yourself to the Limits
You set mental barriers for yourself every single day. Every time you do this you are re-enforcing what you thought and your brain makes it into a reality. What I mean by this is, have you ever thought about getting a lot of studying done at one time? Then when you got started you said to yourself that you couldn't ever learn all of this? That is the conditioning you have done to your brain all these years. This is why you should set for yourself some small, yet achievable goals that are still outside of your comfort range and reach them. This means things such as reading a chapter in a book, working for an extra 15 minutes before breaking. There are plenty of ways for you to push yourself all you need to do is find yours and break down your mental barriers over time.