I agree with gargoyle, finding your right key is imperative. I have a low voice and find G, A, and E easiest to sing in. I also agree with Don, that it is important to find songs you care about...I started out with simple 2 chord songs, like I Am a Lonely and a Lonesome Traveler and Drunken Sailor, songs where the rhythm is fairly obvious yet not clunky (I long ago realized I'd never make it if I practiced songs I didn't like). It is a bit like rubbing your stomach while patting your head, but the pleasure that results from getting it right, even for a measure or 2, will provide lots of motivation.