There is an art and science to grant writing.  So do your homework.  If the grant form is not filled out properly and/or doesn't have the correct format, it will automatically be rejected before it's even read or reviewed.  Each non-profit organization also has different rules and regulations in the way they accept applications.

Volunteer Center is also a good source.  Volunteer centers are operated by counties or cities.  The one in my county provides classes on grant writing.   I would assume other volunteer centers will also provide them.

Most writer's are on commission.

Find a niche and a cause you are passionate about.

Daddyshome, Inc could use a grant writer.  If you want to get your feet wet with Daddyshome, contact us through the website at www.daddyshome.org

Good luck.

My wife writes several grants a year (though she is a physician), and receives most of them.  That being said, she is pretty focused in the medical world.  It does take a whole lot of time, and you may want to try and find someone who can review the grant before you submit it.

As people have stated above, you need to know a lot about your target audience.  But if you turn out to be good at it, there is a ton of money out there.

Good luck!