Hang out in the area and see who's about. If someone catches your eye, give a little cough to let him know you're interested. Be wary of non-cruisers and dog walkers. Truckers use the area daily, so wait for them to initiate. Reps and married types will be a little cautious - get out of your car and walk around, or flash your inside light once.
Are you planning to be here later? Have you been here before? Let other guys know by using the comments below.