Which park are they going to? Here are a few general hints:
-Shrek, Jimmy Neutron, Hulk, and Spider-Man are the attractions everybody goes to first thing in the morning. Those four tend to have the longest waits all day.
-The Curious George and Camp Jurassic play areas are great for adults as well, especially if they want to get wet/soaked.
-Free lockers are available at Hulk, Dueling Dragons, and MIB. They're only free for about an hour, though.
-The map and insert combination is a powerhouse of information. Many questions you may have can be answered by reading them.