As the Warrant Officer Recruiting website states...your letters should be personal. They should not be general....in other words if I take your name off the top and replace it with mine, if the letter is still true...then its too general. Make sure the letters include things that you have done personally and have the officer or whomever tie that into your character as a person.
Don't be afraid to ask the officials in the area. Congressmen and congresswomen. Judges, police officers, lawyers, pastors, businessmen and business women.
People that are themselves working and striving to better America. Make sure that they know you if they don't present yourself to them, tell them your dream and convince them that you are one of a kind.
Hope this helps.