Careers Advice is a UK site that provides a pretty accessible step-by-step process for writing a resume. If you have students use it, though, you want to make sure they understand that a “CV” is another name for a resume.
The same group also has an interactive Career Values Tool where users answer questions to help them identify the key elements of a career right for them. It’s interesting, but has more limited value, I think.
I’m adding the resume-building site to The Best Places For Students To Write Their Resumes.