The symbol for parachuting activity, a drawing of a parachute is probably the easiest to remember and to identify, although skydivers themselves may be very tough to spot, especially during freefall before they open their parachutes. Be sure to listen to the appropriate unicom or other radio frequency for the nearest airport to find out whether there are currently jumpers in the area. You can expect to hear reports from the pilot of an airplane full of jumpers as the aircraft approaches its intended altitude and as the first and last jumpers are away. You also may hear estimated times to landing for groups of jumpers. As always, if you don't hear any activity on the radio, ask.
The symbols for gliders, hang gliders, and ultralights are nearly identical. Look for the silhouette of a glider, complete with long wings, and a letter surrounded by a diamond-shaped box. The letter tells you what type of activity the symbol represents. G is for glider activity, H is for hang glider activity, and U is for ultralight activity. As you scan the area for the expected traffic, keep in mind that gliders don't necessarily move the same way other aircraft do. You should be accustomed to scanning for other airplanes as you fly, and you may expect to see aircraft traveling in relatively straight lines at fairly constant altitudes. That's not usually the case for gliders and hang gliders, which cannot fly along a straight course and maintain altitude. You are more likely to spot them circling tightly in thermals in an effort to gain altitude or gradually losing altitude as they glide along a straight course.