Soror
I am a longtime federal employee (10 years this year) so I know all too well about the frustrating process of trying to get into the government.
USAjobs is a great place to start to find out where the jobs are but the hiring process is SO painfully slow. I know -- I've been looking for the last 2 years and 50 applications and 3 interviews later, I'm still in the same place
If you've got a Master's degree, you should look into the Presidential Management Intern Program and the Federal Career Intern Program. These are great opportunities for getting your foot into the government.
sayhi2tinee