I work for NOAA/NWS/NCEP, am not a forecaster like most of the folks looking for work on this board seem to want to be. I used to apply to all the intern jobs like everyone else but no dice. I turned down a forecasting job in the private sector right out of school, then got hired as a Support Scientist at the University of Northern Iowa. I am fairly certain that my internship (UCAR/COMET) was 75% responsible for me getting the first job, in addition to my grades, and being active in SCAMS. Alot of what I did at UNI was computer-related, I came out of there being an adept administrator of Windows/UNIX/Linux, shell scripting, GEMPAK, WRF/Workstation Eta modeling, web stuff. I then took a job in NC as an air quality meteorologist after 4 years in Iowa, then saw the announcement at NCEP/NCO. My experience at my job in Iowa pretty much got me my current position, because of my experience with shell scripting, computer administration and experience running numerical weather models. Plus always have stellar references.
For me it was hard work and alot of luck, one thing led to another, and the pieces all fit together. I couldn't get a forecasting job at a WFO now probably, but I think I'm past that now anyway. I don't know exactly what to tell you about getting a job with the NWS now, other get an internship in school and be amazing at it, so that you have sterling references from it. Don't overlook the private sector, right out of school, get experience doing anything at all, anything computer related, GIS, community outreach, etc. And when you are somewhere and have stopped building skills, move on to another position. Don't be afraid to move anywhere. At the beginning of your career you shouldn't stay anywhere long. Build a resume with varied experience, everyone and their brother has a Met degree. Looking back, I'm sure my Met degree didn't get me any jobs, it was all the extra stuff that did and learned along the way that tipped the scales.