One of the best networking tips for shy people might be simply "Move your desk at work."

Jeffrey Pfeffer tells a powerful story of a manager who attributes his success to his decision of where to sit.

…After carefully studying the facility layouts, the new director of engineering decided not to occupy his office in the so-called Executive Row. He noted that during the course of the day, people walked to the cafeteria and to the washrooms. He found where the two paths tended to intersect, near the center of the open plan office layout, and took that position as his work location. He attributes much of his subsequent success to that simple move, since it gave him much better access to what was going on in his department. He could keep on top of projects, answer informal questions, and in general, exercise much more influence over the activities of the unit than he could had he been cut off by himself. [Achieving Success Through Social Capital: Tapping the Hidden Resources in Your Personal and Business Networks]

You may have more control over where you sit than you think you do. When you start a new job, for example, you may be given the opportunity to pick between various offices, cubicles, or desks. Or you might have the choice of which floor to be on. Even if you don't, you can request to be relocated when a vacancy opens up. Consider traffic patterns and identify the natural crossroads. You may also consider where others are sitting, and take a place in the vicinity of those whom you would like to meet. Proximity is a big determinant of interaction.