The sample approach above was really intended for anyone coming in to academia from the outside (young students need not necessarily have any skill to offer and only need to show clear intent/interest/competence).

If you can bring value to the relationship (sometimes interest is enough, but not always), that will make a big difference.

An HN-specific skill that might provide a mutually-beneficial "in": An ambitious experimental collaboration run by some of my physics colleagues once engaged some CS students to overhaul the collaboration's web-page. The result was one of the nicest research webpages in the (large) department.

Offering something like, "I'd really love to learn a lot more about your research -- I've built out a number of sites [1,2,3]. Could I work with you to improve your research group's page in return for helping me understand the subject-matter better as I go?" may get some replies. Make sure the relationship is mutually-beneficial and not exploitative :) (at a minimum, it can go on your resume).