I like to see some of the projects that candidates have worked on before. So in addition to my asking my standard interview questions, I can ask questions about the real projects that they have worked on in the past. This way, I can probe with harder questions, since if you've worked on the project, you should understand it pretty well.
So in the EE field projects can be circuits that they've designed and built in the past, or programs that they've written, or ICs that they've designed, etc.
For you in ME, it would be things that you've designed and fabricated, design projects that you've been a part of (like building solar racecars or robotic things, etc.).
What kind of things have you designed and built so far?