A startup CEO and former Googler says these 4 mistakes make you seem unqualified in a job interview

A job interview is your chance to make a killer first impression and prove to the hiring manager that you're the best person for the job.

But sometimes nerves get the best of us - or we just don't prepare properly - and we end up doing things that discount our qualifications and make us seem irresponsible or incompetent.

"I've easily conducted over 200 job interviews in the past 12 months," says Liz Wessel, CEO and cofounder of WayUp, a site used by hundreds of thousands of college students to find jobs at places like Microsoft, Uber, Disney, and Google, where Wessel previously worked. "Even the brightest and most experienced candidates seem to have issues following best practices for interviewing."

She says these are some of the worst mistakes job candidates make in (or before) interviews that can make them look seriously unqualified: