1: I moved (by chance, wasn't planned as part of a "reawakening"), which was awesome, the change of place let me reset my bad habits. We are creatures of habit and changing that habit is much easier with a change of scenery.
2: I started running. My first week, I jogged about 100 yards, then walked about 400 yards, repeat 4x for about a mile total distance, it sucked and I hated it, but I knew it was the right thing to do. Week 2 I was up to running about 125 yards and walking 375 yards. Week by week I slowly increased my fitness, and eventually ran a mile without stopping, then 1.5 miles without stopping, then 5 miles without stopping (took a while lol), etc.
3: I realized that one key to weight loss was my addiction to food, so I adhered to a very strict diet of chicken and vegetables 3x/day, and nothing else.
4: no alcohol, socially or otherwise
What kept me going was strict discipline, and making sticking to my plan, making it my priority above everything else. For eight months, the one thing I existed to do was improve myself, and it ended up working. By the end I was at about 215 lbs from 315lbs (im 6' 5" btw), I was happier, I had better relationships, I was more confident.