Your writing skills seem pretty good. What you need to do is practice speaking, especially answering questions that might be expected in an interview. There are, I'm sure, lots of websites to give examples of interview questions.
Be prepared with answers, then you won't have to worry about putting together sentences on the spot. You should especially be able to describe projects you have done in your schooling. HR people will care a lot about personality questions, but the engineering managers will want to know what you can do in engineering and how you can explain that to colleagues and clients.