When you have narrowed down your choices, make your applications. Be aware of deadlines, as they will vary from one school to another. These are usually absolute deadlines, and if you miss them, you'll have to wait for the open application period for the next available term. Each application will require a fee, so you likely won't be applying to more than a few, but don't put all of your eggs in one basket.
If you need written recommendations from others, be sure to ask early enough and clearly identify deadlines. You should pad your dates so that if they are late, you still have time. Remind them at least ten days before the deadline. Be sure to thank them appropriately.
Never assume that because you have a 4.0 you're a shoe-in. Someone with a lower GPA and tons of community service and extracurricular activities may just beat you out. Read about the student population. Know what they look for in a student, and work to highlight your qualifications that fit that mold; or find a better match for yourself. Schools are usually well aware of the academics of the schools from which they usually accept students, so don't try to embellish your qualifications beyond what you can actually live up to. But don't forget to think outside the box and give yourself credit for your accomplishments.
Be sure that you provide all of the information requested. Be neat and organized. Your application represents you to the school, so be sure to put your best foot forward. A messy paper with coffee stains, or ink that's too light because your pen just ran out, will not make a good first impression. If you have to write an essay, give it plenty of thought and polish it.
The competition may be very fierce depending on the type of program you are entering. This is especially true for nursing students. There is a tremendous shortage of nurses, but there is also a shortage of nurse educators, so the programs have a limited number of openings. There are waiting lists, and schools use many tactics to weed out those who are not serious or likely to complete the program.
It will be several weeks or even a few months before you hear back from schools. Usually they will include information in your application packet as to how long the process takes. Relax, and hopefully you'll get into the school or program you most desire.