You've made the decision to burn your candle at both ends by having a career and earning an education. After putting in a full workday, most people enjoy a few hours of relaxation each night before going to bed and doing the same thing the next day. How are you going to maintain a high level of concentration when you're brain is begging you to chill out?

One suggestion is to pace yourself. No successful person can stay in high gear constantly. You've chosen a path that necessitates endurance. Good marathon runners keep a reserve of energy throughout an entire race. In order to keep going, they have to know that if they start feeling tired that they have something deep inside them to use in order to finish the race. You need to do the same. If you find your mind wandering while at work or in class, you know you haven't paced yourself properly. Be sure to take breaks. Go for a five minute walk around your office building. Grab a snack at the local sandwich shop. Read an article from the day's paper. The time you spend taking breaks will be worth it when you're that much more focused at work or in class.

Remember that concentrating is easier if you divide your work up into small parts. Set mini goals for yourself throughout your day. Once you get that mini goal done, take a break. Eventually, you'll be able to expand the scope of your mini goals and take fewer breaks once you get used to knowing there's a light at the end of the tunnel.