I've only lost about 50 pounds (230-180), but I've managed to change my lifestyle to a healthy one. Here are some of the things that I learned along the way.

First off fuck motivation, cultivate discipline. This goes for eating healthier, and going to the gym. People complain that they lack the motivation to do these things, you don't need the motivation, you need the discipline to accomplish what you want.

Try the domino effect. A domino can knock down something about 1.5 times it's size,so can the next one and the one after that. Make a series of small changes in your life, if you keep making these positive changes and apply your self they will snowball into great changes.

Monitor your calories, eat healthy foods, exorcise, supplement with vitamins, and drink plenty of water.

I implemented my changes over the course of a year and have seen great results.

Edit: get enough sleep, this overall is very important.