Have a vision. Consider the PMP as you will a project. Prepare a plan of action. Set a deadline for when you're going to take up the exam. Ignite yourself with the desire to clear on the first try. Read success stories of people who've cleared at the first attempt. Get yourself into exam preparation mode.
Find out exam details. Search for information about the pattern of the exam, the books recommended and the areas that people consider challenging. Don't lose heart when you find there's so much syllabus to cover. Remember, it's not possible to cover every single thing -- what you need to do is focus on key areas.
Enroll for a course. Anyone taking up the PMP is required to take up a minimum 35 contact hours of project management training. Select a training course, preferably one that is PMBOK based. This will help you get familiar with PMI lingo that will figure prominently in the PMP exam. The middle of an exam is the last place to be trying to comprehend what exactly a given term means. Make sure your course provides you with many opportunities for taking up mock tests to help you gauge your preparedness.
Focus on application, not memory. Although the PMP has questions about inputs and outputs for PMBOK processes, their proportion is not very large. So don't gear your preparation towards memorizing those formulae. Rather, concentrate on learning to discriminate the formula a given situation warrants. Pay attention to getting your basics right -- this teamed with the hands-on project management experience of your job will help you crack the PMP.
Take up mock tests. As you continue studying, take up mock tests. This will help you evaluate the areas where you need greater preparation. Revise those portions where you score less.