Well when I showed up for my interview I came after work I was covered in road salt, but we sat down and talked and I gave answers based on my experiences and at the end of the interview they offered me a job. You probably don't have to wear a tailored suit just nice work cloths. Clean pair of black work slacks and like a button up or down collard shirt tucked in wear a nice clean pair of work boots, should be no problem. Then just be charming and nice. The phone interview is drivers license number and there going to tell you a little about the job and basically see what you know about the industry and show them you are interested and want to work there.