I'd say the usual combination of eating better, watching calories and doing as much cardio as reasonably possible should work, might want to get your thyroid gland checked, if it's not working well it's gonna make loosing weight a loooooooot harder (and it's easy to fix, they just give you a smoll pill to make it work gooder). I'd also recommend seeing a nutritionist to help you with the whole food side of things, if you're in Canada you can ask your family doctor and he'll happily send you to one.
If you're feeling extra, join an MMA gym, lost 120lbs in a schoolyear's time that way lol.