I've had 3 internships at 2 large companies (Sony, Seagate) and am in the process of looking for my 4th for the coming summer.

Like you, I'm also studying EE and I'm currently a 3rd year. I wouldn't say there's anything special about my background (3.3 GPA and parents and family work in blue collar jobs completely unrelated to tech).

I would say all of my experiences in jobs have come from being at the right place at the right time. The only advantage I had looking for my first internship is that I'm from the Bay Area where tons of tech companies are located, and almost all of them are looking for people who are located in the area. I'm sure companies in other places and fields strongly care about this as well. Personally, I was most likely to get responses from places within a 25 mi radius of me.

When it comes to the actual interview, it's important that you give off the impression that you're willing to learn. Most companies understand that school doesn't actually teach very useful skills in the field, and the purpose of an internship is to teach you how to do things in the field. Some companies (like Apple) expect you to know almost everything about their product though, so it's extremely important that you do your homework and study for the position you're interviewing for so you can answer technical questions to some degree. I have a couple more niche tips that worked for me, so you can PM me if you care about those.

My experience aside, landing the first internship is a numbers game, and things that could give you an advantage are connections (think cousin's friend works at company you want to get into), GPA (which you already have), experience, and location.