Alright, I'll share what advice I can.
Being physically fit isn't nearly as hard and most people imagine it is, so don't worry, you can do this with a little bit of effort.
First and foremost, the absolute most important thing you can possibly realize is that a plan will only work for you if you stick with it. I think this is where most people fall short, and get discouraged. Do not attempt any of those fad diets or miracle pills or what naught. Even if the plan doesn't give you results as quickly as others, if you stay with it in the long run, you are much, much better off.
Alright, as for the plan itself, as cliche as it sounds, diet and exercise are the real solutions. Most people take this advice to extremes and make a plan that even an athlete would consider severe, I'll detail about what you should be doing for someone of your body type.
Diet is the number one place where the difference will be made. Someone of your size could probably do no extra exercise apart from standard walking and lose weight with the proper diet of reduced calories.
The first thing you need to do is find out how many calories you actually need to sustain your current weight, then eat less than that. This can be done easilly on various websites, such as the link listed at the end of this paragraph. You might want to do it again with your more accurate data, but from using the OP information you need to eat less than 2600 calories per day, assuming you don't regularly work out. This site recommends less than 2150 calories daily as a fat loss measure.
Calorie Calculator - Daily Caloric Needs
Next you have to decide what to eat. When most people think eating healthy, they think to extremes again, and imagine themselves like those health nuts. This of course is likely to be given up on. You don't need to eat like that, you just need to be conscious of what you do eat. A few simple guidelines will be all you really need, in addition to the paragraph on caloric intake. These are in no specific order, and are just tips.
1) Take lean meats over fatty ones. Given the choice, take chicken or fish over beef. Deli meats are a fantastic alternative, regardless of which you choose. I practically live off chicken breasts bought in bulk from Costco.
2) Don't use condiments, they are unnecessary sources of "empty" calories.
3) Try to limit carbohydrates, which are any sort of breads and grains, and especially sugar. You do need some, so don't skip it entirely, but choose complex carbohydrates such as whole grain breads over simple ones, like sugar or white breads. A good amount to shoot for is 100-150 grams per day, and you can check the label for how much a serving contains.
4) Try to avoid sugars entirely (not including the sugar in fruits, or real juices), you don't need them. I know it's hard, but it will make a significant difference. Simple sugars are extremely easy to convert to fat, so they are kept around more as fat if you don't use them all, unlike complex carbohydrates.
5) Leafy green vegetables are your friends. Filling, low calorie counts, great vitamins, and unlike fruits they have no sugar. Avoid dressing if you're eating salads though, it sort of overrides the benefit of the greens.
6) While the rest are just tips, I am going to mandate one rule, sorry. You are only to drink milk, real fruit juice, brewed tea, or water, with water being preferred. This may seem harsh, but it is very important. When counting calories, nearly every single person forgets to count the calories in drinks, which can add up to a huge amount. Be very, very aware of it.
7) For the same reason, try not to snack in between meals at all. If you absolutely have to eat something, opt for something like a piece of fruit, or a serving of vegetables. Also, if you do, remember to count the calories toward your daily total.
8) Not really a necessary thing, but I did find it helped me to space out my meals to four-six meals a day (less calories per meal, meals more often) because I found I was less hungry during the time between. It's also said doing this makes your metabolism more effective, but I'm not sure how much truth there is to that. Make absolutely sure you're still obeying your calorie limit.
9) Keeping a log of everything you eat will really make you conscious of what you are taking in, and will help keep you motivated.
Exercise is the other side of the equation. Weight loss is mostly physics, in that it all boils down to using more calories than you intake. When most people think exercise for weight loss, they think running. While running is arguably the most effective way, there are plenty of alternatives, which could fit your goals and drive more closely.
There are two basic types of exercise, aerobic(commonly called cardio) and anaerobic (think like weightlifting). Past a certain weight, either of these methods will help a person slim down, because both can boost metabolism. What we have to do is figure out what balance is best for you.
Please don't take this the wrong way, but I think it might be hard for someone of your stature to stick with running. It's an enormous stress on the joints even for slim people, and lets face it, running isn't very fun. I would personally recommend swimming if you have the option, as it seems much easier to stick with, will not harm your knees, and seems at least to me a significantly better experience. Start off slow, maybe 4-8 laps twice a week. You will find that you don't need a significant amount of exercise to start losing weight.
Weight lifting is my personal choice for main source of exercise, and while I can't say it's right for you, it is usually my recommendation for those beginning to become fit. First off, its not tiring like cardio is, and secondly you can see near immediate results, going up in weights nearly daily at first. People don't generally consider this method when aiming to lose weight, but it WILL boost your metabolism, and as a plus excess calories will go towards muscle instead of fat. Just be sure to do it right. I would suggest searching google for a beginners 2-3 day a week routine. You can even combine the lifting days with the cardio days. Two to three days of decent exercise don't seem like a lot to ask, and will make a significant difference. Keep a log of how much weight you lift, or how far you swim/run, and you will find it really helps keep you motivated. One concern that many women have with lifting is that they will get "bulky" and look masculine, but this is not something to be concerned with. It is incredibly hard for women to bulk up, and you can't do it by accident. That being said, make sure your lifting remains challenging, going up when appropriate. Too many women stick with the super low weights, and are just going through the motions, not actually helping themselves.
As a final thing, I have one suggestion that may sound a little strange. Only weigh yourself once a week, preferably at the same time of day. Many people will constantly weight themselves, and get discouraged that nothing is changing on an hourly basis. These things take time, and if you watch the change too closely, you'll lose motivation.
Please PM me sometime, and I will give you my direct contact information. Fitness is my hobby, so I'd be more than happy to hold your hand to guide you toward your goal. I know enough about it that I'm confident I can get you there if you stick with it.
-Umaro
EDIT: My offer goes for anyone interested, just PM me.
I am an obese person. I am 5'2" and weigh 270 lbs. I am wanting to lose weight and get down to 150 lbs at least. So I have started a personal diet and exercise program. I am going to try to burn more calories than I eat every day. Anyway, I was wondering if you all could offer me some support plus advice and tips? 
I would greatly appreciate your support during this time of weight loss for me. Thanks.
