Many good comments, so I won't repeat them.
From my experience, ATTITUDE is everything (well, most everything, you gotta know what you are doing, too). Be nice, be informed, be on time, be available, and look for opportunities. Early in my tenure with my last employer (about 1 year), I asked if they wanted me to go to the construction site to make sure the equipment was installed properly (at the time we did design/construct projects). They were surprised, but said "sure, go for a few days". In the end, I spent 1-2 weeks a month at the site for about 8 months. I helped a lot, but I learned a whole lot more.
More importantly, career-wise, I was visible to the higher-ups. I got to work with many project mangers and several VP's. After my experience, it then became the norm for the design engineers to spend more time in the field.