Sloppy applications give a bad impression about you. Choose your references carefully. Select those professors who know you and your work. Give your reference plenty of notice about writing letters of recommendation. Do not approach them at the last minute.
Many programs require some type of written statement.
These statements can be a biographical statement, a statement of your goals, an account of the important life experiences that resulted in you applying to graduate school, or why you are applying to a particular program. Some programs require you to write an essay on a topic they provide. It tells something about yourself and provides a measure of your writing skills and your ability to express yourself. When writing these statements give yourself lots of time. Answer the question that you are asked.