Your two ideas are a great place to start. Take voice lessons regardless. Even if you're just playing guitar in a band, having the ability to play and sing harmonies is a good selling point. What city do you live in? Is there a "scene" that you could squeeze into? I've found that playing music is one thing, but if you can befriend the "gatekeepers" and "tastemakers" in your city it will much easier to get ahead. Over time you can even become one.