Get the support of your work supervisors. Make it clear that school will not interfere with your ability to do your job. Find ways that your new expertise could benefit your company in the long run, or that having a personal connection to a large student body could benefit your company in the short term (if you work in sales, for example). Point out that attending school will tighten up your priorities, improve efficiency and hone your problem-solving and project management skills.
Choose your school carefully. Don't just consider the degree program's reputation and price of the school in question, but also look at the commute times between your home, job and campus. Many universities have programs designed for adults returning to school, which accommodate a full-time working schedule. You may also want to look into online degree programs, which are designed to work around your schedule.
Get the support of your professors. With an increasing number of adults returning to school for advanced degrees, many professors are willing to work within the confines of a student's tight schedule. If you can't attend a required event due to work constraints, talk to your professor about alternatives, but don't abuse their flexibility. Make all deadlines for projects and show up to class with your assignments completed.
Create a schedule, and stick to it. If you can, commit yourself to spending half of each lunch hour on homework, and two solid hours each evening studying without interruption. Let your friends and family know these times are off-limits for them to contact you. Turn the phones off, keep the TV off, and stay focused. Head to a library if it helps limit distractions. Set aside blocks of time on weekends for study as well. But don't forget to set aside time for fun, too. Let your friends know that Friday nights are for them, and do something meaningful and relaxing with your night off.
Take advantage of summer courses. An easy way to lighten your course load during the school year while staying on track with your degree and still working is to take a class or two each summer. If your program doesn't offer them, see if you can take one at another local university and transfer the credits.
Consider independent study, if your degree program allows it. Design your own course around a topic that interests you, and find a professor willing to monitor your progress. It can be extra work to arrange, but without rigid meeting times, the course will be more flexible than other classes. If you don't want to do it alone, find a few classmates interested in a similar topic, and design your own course together.