First, arrange a formal meeting with each of your professors to ask them whether they are willing to write you a letter. Send each professor an email specifying that you want to meet about getting a letter of recommendation and specify the program (e.g., Masters in Counseling). Asking a professor on the fly may not allow them to recall fully your academic performance in their classes. Never simply send a professor recommendation forms without first clearing it with the professor.
Second, at the meeting make sure to ask whether the professor can write you a positive letter. You want a letter that will help you get into graduate school or professional school, or will help you get an internship or job; you do not want a letter that hurts your chances.
Third, after the professor has agreed make sure to give them the necessary information way in advance. This means at least two weeks before the deadline. In addition, you should provide addressed and stamped envelopes for the professor. Moreover, if different places want different things or have different deadlines, you should provide this information in a spreadsheet (you may download the template below) to the professor with these details. Also, in the spreadsheet make clear which schools need hard copies and which schools have online forms.
Finally, after completing the steps above, if you want a psychology professor to write you a letter of recommendation, first complete the Psychology Reference Request Form. and the Graduate School Listing spreadsheet. Download those, type in your answers, and then give them to the professor, along with your personal statement, unofficial transcript, and CV. Ask the professor their preference in terms of receiving an electronic copy or a hard copy.