1. First, choose the vocal style you want to sing (rock, pop, country, alternative, etc.) based on particular songs you like. Then choose an easy song in that genre.
2. Now listen closely to the artist singing. I find that headphones are good at this point because they help you zoom in on the intricacies of the vocal performance you're listening to. Listen like you're holding an aural microscope to the sound.
3. After listening a few times, start miming with the singer, SILENTLY moving your mouth, face, tongue, etc. trying to imagine in your mind creating the exact sound and pronunciation of the singer you're listening to. Literally let the intent to make the sound teach your automatic nervous system to sing.
4. After you feel confident miming the song, start putting your voice to it. IMPORTANT: If you're wearing headphones, take half an ear off so you can hear what you are really doing. Don't sing with both sides on ... you'll fool yourself.
Let me know if you decide to do this. It's also a great way to learn a new musical style.
Power, Path and Performance training... when voice matters