If you are fortunate enough to know someone else that wants to lose weight and clean up their eating habits, why not take advantage of that and do your best to help convince him/her to join you. More often than not you will have better odds of sticking to your diet with a friend to eat and compete with. The best thing to do is surround yourself as often as possible with others that also diet and exercise to keep yourself motivated and not feeling like you’re doing something so drastically different than you should be doing.
When living with someone else whether it be your partner or family, for the first few weeks of the diet you will want to do your best to limit your access to unhealthy foods. Try to get them to understand that if it isn’t necessary to them (which it shouldn’t be) to have desserts and fatty foods in the refrigerator or in the closet, that they need to come out. No sense leaving stuff around in plain site that could cause you to relapse back to eating junk food and stop you from ever getting past the three week mental and physical barrier diets can cause. Also do yourself a favor and post up the list of diet foods and schedules (you should have created or obtained this) somewhere in the kitchen and let everyone know how important it is to you to stick to this. That way everyone else around you always remembers not to cook for you and to let you do your own thing. Cook for yourself don’t let someone else screw up your diet because you were too lazy to prepare a meal.
Look into grabbing a dietitian to help you out along the way if you feel you’ll need extra looking after, or just need more help planning out your diet from the beginning. Chances are this won’t be necessary though as you most likely chose a popular diet that has already been well outlined in books that are very easy to follow. If in fact you definitely need more advice along the way, look into joining the many dieting forums and chat rooms all over the web as there will definitely be other dieters willing to give free advice.