Think about your nursing objectives. If you want opportunities for high levels of responsibility, high wages and administrative duties, then you'll need to plan for more than a two-year associate's degree.
Consider how much time you have. If you have kids or a great job you don't want to give up, you might want to take some online courses so you can fit classes more easily into your schedule. This is easiest to do in the early stages of your nursing education, since you'll be dealing with basic courses instead of more advanced clinical work. Some programs are completely online.
Look at your finances. If you can't afford to take on a full course load even with scholarships and financial aid, then you'll need to add a minimum of one year to your study. Online courses typically are cheaper.
Examine your personality and needs. Be realistic about how much "me time" you need and spread out your courses based on what you comfortably can handle.
Determine at what point in your degree program that any clinical courses or internships are required. Some programs are hands-on almost from the beginning, while others don't have you in rotations until your last few semesters. Your clinical work will be less flexible than other courses, so you should base your other work around the clinical requirements.
Study the course bulletins from the nursing school you want to attend. Since nursing course work typically becomes increasingly advanced, nursing programs highlight the requirements by semester or year.
Consult with nursing advisers or nurses you know who already are in the nursing field. They can point out parts of the bulletin schedule that may cause you difficulties and they can suggest alternatives. They also will provide advice about why you might want to take one class before another if the bulletin allows for flexibility.