The graphic in the bottom right area of the screen indicates some of the types of Pokemon nearby, with the number of footsteps indicative of how far away they are from you. To track a Pokemon, tap the bar to bring up the full list, select a specific Pokemon to highlight it, and then start walking. The footsteps will either decrease, or increase until the Pokemon disappears completely. If the number of steps decreases, it means the Pokemon is getting closer. This method can be used to track a Pokemon until it appears.
If you walk in a direction and more steps appear, try turning around and walking in another direction until the Pokemon gets closer. When the Pokemon is down to zero steps, it means it’s very close to you! Simply select it, and wait a few seconds for it to appear. You’ll also notice pulses that emit as you explore the map. They indicate when major changes have occurred in the availability of the area’s Pokemon.
Originally Posted by: gamespot.com