Matriculate, a free college advising service, works with students who have a 3.5 or higher GPA and whose families earn no more than $80,000 a year, matching them virtually with student mentors at elite colleges to provide insight and advice about college life and the admissions process. High-school students who use Matriculate, compared with those lacking any support, are 25% more likely to attend top colleges, according to research by Ben Castleman, a professor of education at the University of Virginia.