In your case, the first thing you have to do is enunciate. Slow down and speak each word clearly: there's... a... red... house... over... yonder... When you are able to speak clearly, then put the words together like a guitar solo. As a singer, your biggest enemy is your guitar. Your guitar sits on your voice like a ton of bricks. Until you beat or match the tone and expression of your guitar solo, you will always be a wimpy singer. Your singing in NYC was an improvement, though. Know your range. It's more important to be comfortable and confident than to hit those hard to reach notes.
By the way, vibrato isn't in the head. It's in the throat and chest.
