The best things to do are 1.) be yourself-- enthusiasm and friendliness put them at east. 2.) Find out about them. Open-ended questions and what their interests are, I've found, helps them to decide on what career they'd like to enter. Perhaps you have a quick story about their interest that helps you 'relate'. Once they open up, you can find out their fears about college and address each issue individually. Many of my students-- even now-- are first-generation and aren't getting much info from their HS counselors about crucial college-related items. You may need to cover some of that ground, but slowly-- so they're not overwhelmed by info overload.