Know Your Timetables....
It's my experience that high school kids have alot on their plate already as they enter junior year with a schedule filled with AP and IB classes. Then there are the added responsibilities of SAT/ACT review classes and testing, college visiting, college list development, requesting recommendations, developing resumes and increasing their involvement; all add up to a very stressful time.
Seniors are then confronted with the application completion and filing process, essay writing, interviewing, additional visiting with overnights, a tougher schedule than junior year and perhaps more testing.
Parents can help them manage stress by knowing what the timetable is for the entire college admission and financial aid process. Gentle reminders can then help their college-bound son or daughter stay paced and meet deadlines.
I would suggest having a conversation at the end of sophomore year about the upcoming junior and senior years outlining the timetable and coming to an agreement about what part of this process you, as a parent, could handle to relieve their stress. You may need to revisit these details as you move along, but laying the foundation early can help avoid stress during the application process.