I'm sure there are some well thought out diet books or plans that actually work, but my attitude was always, "Just be smart." The thing is, most of us know what eating healthy looks like: more fruits and vegetables, less red meat, less fried stuff (sorry), fewer soft drinks, etc. It also means more grocery shopping and less eating out. You know what it takes, and it's going to be hard. But you also know it's going to be worth it. Don't do anything drastic, though, unless you want to lose weight quickly for a couple months then gain it back with an additional 10 or 15 pounds extra. You know what it takes to eat healthily. Just do it.
4. Find Something That Works For You.
If I had started my journey and said, "I really want to be good at yoga." My journey would have been more like the Titanic rather than Christopher Columbus. Do you despise running? Then don't. Do you hate staying in one place? Don't use the elliptical. You have to want to keep coming back, so do something you can enjoy.
5. Keep Stats.
There's your weight, obviously, but don't just rely on the scales to show you how far you've come. Write down how long it took you to run your first mile, your first 5K, whatever. If it has a number, and you are looking to improve it, record it somehow. Yes, seeing numbers drop on the scale is phenomenal, but so is seeing numbers fall off the stopwatch and your belt holes.
6. Know That At First, You Will Suck.
The first stationary bike session you complete? It's going to suck. The first time you swim down the fitness center pool and back? Suck. Your first lap you do around a track? Suck, suck, suck. But the important thing to know is that you will get better. And the better thing? It won't take very long. If you heed to rule No. 5, you should start seeing improvement in a week or two. And after you get to where you can comfortably do some cardio workouts for 30 or 45 minutes, you will start improving even faster.
For example: I started my journey on January 1, 2009. I completed my first 5K in 40 minutes & 14 seconds. To put that into perspective, the winner could have done it twice. In the half-mile, a 75-year-old lady walked past me, patted me on the back, and said, "You can do it, son." Then 55 days later, I did another 5K and finished in 29 minutes & 10 seconds. It took me less than two months to take 11 minutes off a race that isn't long (in the racing world) to begin with. Yes, you will suck at first, but you will get better. Promise.
7. Set (Realistic) Goals & Keep Them Short-Term.
If you go into this thinking, "I have to lose 200 pounds. Let's get started," you will be overwhelmed and your chances of failing will skyrocket. Break it down into small increments, maybe 10 or 15 pounds at a time. You're more likely to stick with 10 pounds in two months than 200 pounds over two years. Reward yourself when you hit big milestones (depending on how much you have to lose). Better yet, get someone to reward you; you'll save a lot of money that way.
8. Be Prepared For Failure.
You aren't going to be perfect. There are going to be many times when you eat way too much pizza at the football party or skip four workouts in a row. The crucial thing here is to anticipate these moments, move on from them, and put yourself back on the wagon. A few missed workouts will not erase your hard work and a few thousand extra calories will not put the pounds back on. It's going to happen. I've been there. It's easy to feel sorry for yourself and give up, but don't. You don't want to go back to the beginning.