Before i started voice lessons i was convinced i was a Baritone, but after months of warmups my teacher told me that i was a tenor. I still happen to disagree with her, but she is the one who gets paid. The exercize that helped me most was doing 1 3 5 or Do Mi So on a Ya. Go up in half steps. When you get to notes that feel high.... make sure to stay relaxed. It should kinda feel fuzzy, and u'll hate the way it sounds to you, but you'll get used to it. Good Luck!!