FWIW, here's what worked for me:
#1 - Go to the gym... Start with 45 minutes of cardio 5 days a week & about an hour of weights 3 times a week. Change up your weight routine about once a month. Change up your cardio routine every season. Get a trainer if you can afford it - at least until you know what you're doing. If not, ask people you see at the gym regularly for workout tips - not the body builders, those guys are too crazy for you. It will really help to be accountable to someone else, whether it's a trainer, a workout buddy, a spouse, even a co-worker. This person has to see you on a regular basis and be committed enough to give you loads of crap when you slack off and congratulate you when you get results.
#2 - Don't eat big meals - more smaller meals will support your metabolism better. I'm talking about five, six, or even seven meals a day. It's all about evening out and monitoring your calorie intake. Ask your doctor about your daily calorie requirements or get a referral to a dietician. It's best if you can talk him or her in to actually doing a quick test. The doctor's formula and my test results were off by nearly 900 calories. Fad diets are temporary at best.
#3 - It's damn near impossible to drink too much water, but you should try to every day.
#4 - Take a good multivitamin. I've heard Centrum is crap - very little gets absorbed. I suggest this because I've also heard that working out can weaken the immune system when you first start working out.
#5 - Pills, meal bars, shakes - none of them helped me enough to justify the cost.
Talk with your doctor before starting any exercise program or diet. You can either jump in with both feet or add something new every month or so... If you're a slow starter, write down when you start the next phase or circle it on your calendar so you're accountable.