Try talking in your normal voice. Then talk-sing... like you're in a musical, having normal conversations with flair. It should still resemble your normal talking voice, as in friends should be able to identify you even when you're doing it. Then embellish this a little bit until it's full-on singing.
Take songs of singers you think you sort sound like (same range, gender) with you in the car and practice singing along everywhere you drive. Do not be embarrassed at red lights. Part of singing effectively is confidence. It's much like acting in that way.