A healthy nutrition plan is the very first thing you should start with.
Stay away from sugars and starches, eat plenty of veggies especially the greens, get plenty of lean protein in your diet like chicken breasts, most fish, lean pork tender loin, and very lean red meat.
Exercise daily if possible. Even if only 10-15 minutes a day, don't think that because you can't spend a ton of time exercising that it's a waste of time. Any exercise at all is better than none. Even if it's just walking though I recommend some type of body weight exercises and interval training if you have very limited time and no access to a gym.
Try to remember, losing the weight in most cases is the easy part, it's keeping it off that can be difficult if you're not willing to make good healthy permanent habits :)
Eat a healthy diet, avoid/eliminate sodas, white bread, white rice, pasta, etc.
Eat lots of veggies and protein and make sure you exercise for ~ 30 min/day.