Here's my advice, for what it is worth:
I am just now starting to lose weight (16 pounds between mid August and now, about 30 days) but I could NOT lose weight for 20 years before that

Seeing a good doc and endrocrinologist definitely helped clear up other factors that were affecting my metabolism.
Everyone's body is different and I would strongly suggest that you get a complete physical if you didn't have one recently. Know your cholesterol, have a basic heart test, know if you have high or low thyroid, etc. Depending on your age, low thyroid can be very common. Low thyroid can affect weight loss, if you aren't on the right med or you aren't being monitored correctly.
Keep in mind that metabolisms vary WIDELY and that they tend to go down with age. Some people can eat a lot and not gain weight. Others (like me) have to limit calories and exercise a lot before losing weight. I am also on a weight loss drug which has helped a lot. I'm not as hungry but I still have to make the right choices. I could still gain weight if I ate the wrong foods and didn't exercise. It has not been exactly easy but it is working.
I do think that drinking a cup or two of green tea helps my metaolism so I do this daily. I found that too much caffeine makes it harder to lose weight so I don't drink diet drinks with caffeine and I stay away from coffee. The green tea seems to be okay, not too high in caffeine. But too much caffeine makes me hungry. Other people say it makes them LESS hungry, so just listen to your body.
MORE INFO: A pound is approximately 3500 calories. To lose a pound a week, you basically have to find a way to cut 3500 calories a week, either by restricting calories or by a combination of eating less and exercising more. Ideally, you should exercise at a rate that is within your "target heart" rate for at least 20 minutes a day...I tend to think 30 -60 minutes is even better...several times a week. The more you exercise, the more calories you'll burn and the more you may lose, over time, IF you don't eat more.
Keep in mind that it takes WLLPOWER to lose weight. You probably will feel hungry but there are some tricks to make that a bit easier. Drink lots of water, stay well hydrated and have a regular exercise program. Try not to eat "on the run" but actually sit down, eat SLOWLY and pay attention to having a nice, relaxed meal, even if it is in front of the tv. Eat regularly, breakfast, lunch, dinner and perhaps a couple of snacks in between to keep your body at PEAK metabolism and to keep from going too long without food.
NEVER go to the grocery store when you are hungry.
Try not to have a SET amount that you HAVE to lose each week. I have gone two weeks in a row without losing a pound and then had a big loss the next week of maybe 3-4 pounds so that it averages out to at least a pound a week...or more.
Hope this helps.