help losing weight

Ok so I need some help losing weight. any ideas would be great. I have tried before with meal planning and small portions and stuff but I would never lose anything. The doc checked my thyroid and now I'm on medicine for that so I'm assuming that is slowing me down. I tried a pill she gave me and 8t helped a lot but as soon as I stopped it i gained weight back. so I just want some tips on what I can do. I know I need small portions and to exercise but what is some things you guys habe done that has worked... I am severely overweight...at my guest was like almost 360 when I was pregnant. so now I want to at least try for 50 to start then a lot more after that!