Learn about your student's educational background before your first session. If you are working with younger students, start by interfacing with students' parents to understand what areas the student struggles with. If your student is an adult, start your first tutoring session by asking this question of the student himself. In either case, have the student read to you from an introductory text during your first session so you can observe his weak areas yourself.
Find out what topics the student finds interesting. This will let you select reading material the student will be more likely to want to read, giving him more incentive to read on his own time. Comics can stir a young student's interest. Use information about the student's interests and weak areas to pick out texts for reading instruction.
In your second session, ask the student to read aloud from the texts you prepared. Be attentive and make a mental note of mistakes, but do not point them out immediately. If the student has trouble with a word, calmly help him sound it out. After the student is finished with the reading, point out the areas where he made mistakes and have him reread the sections. Give one piece of positive feedback for every piece of negative feedback to help your student maintain a good attitude. Give your student homework -- reading a page or two of the text you selected.
At your next session, discuss the reading in a casual, friendly way to check whether the student did the work and how well he understood it. If the student is making progress, ask him to write down two or three thoughts in response to his next reading. Tell your student not to worry too much about spelling and grammar for these responses. If you want to use them, the responses are to help the student think about the reading between sessions, not test his writing ability.
Continue the above process of monitored readings and reading assignments until the student begins to progress. Take notes during every session to monitor the student's progress. Try incorporating games or puzzles on occasion to keep your lessons from getting too routine.