Tracy is right. Find your voice without strain. Lip rolls are the best. I did this for five years myself. I couldn’t sing without this technique. Now I can sing on five octaves. Brett Manning http://singingtosucces.com/ you can watch a vocal demonstration on You Tube. Bret Manning vocal range demo. He doesn’t shove his tequnique in your face. I avoid instructors who say: pitch and diaphragm a lot. I don’t hero worship and singer any more, that I can see their neck veins stand out when they sing.
Haley Williams of Paramore is a student of this. Listen to some of her old and new songs. You will notice the difference. Stop talking during the day, is the best advice I could give to any singer. Your vocal cords are precious. Talk as little as possible.