You want to have enough protein to protect your muscles. This is more important than carbs and fat. To find out how much protein you need, you can use the calculator over here. While it's more accurate to use your lean body mass, it won't hurt you to calculate based on your overall body weight--you might even increase your muscle mass that way.
- Try not to over-think your diet. If it's too hard you'll give up.
- Make sure you have the protein you need.
- Make sure to eat plenty of veggies (two servings each for lunch and dinner)
- Make sure to drink plenty of water (minimum of 2L/day)
- Make sure you have at lest 21g of dietary fiber a day (up to 40g if you need it)
- Include small doses of healthy fats (like 30-60ml of olive oil)
- You'll need a multivitamin, and omega-3 supplements would be nice.
If you have any calories left after your protein and veggies, you can spend them on the things you like. Don't worry too much about the fat to calorie ratio. You'll find that at ~1500 calories you won't have much room for too much of that anyway. NOTE: some people are sensitive to glutens or dairy and tend to hold on to their weight more when they have foods rich in those.
Keep a food diary/weight journal and review it weekly. Also take your measurements at least monthly. If you have a bad weight loss week, double-check your measurements. My wife recently had a 0 weight loss week but lost 15cm overall. If you still aren't happy, look at the types of food you are eating. You may have to adjust it for what your body processes better.
Some veggies pack a one-two punch like Spinach. Spinach gives you about 4g fiber per serving and even has some protein in it.
Also, exercise increases the amount of calories you burn in a day. Anything you do to increase your muscle mass will also increase your BMR. The combination of having higher amounts of protein (meaning 0.5g protein/Kg lean body weight) and exercise will improve your muscle mass. If you walk on a treadmill for an hour you can burn around 400+ Calories. That means you could have 1900 calories on your exercise day and still be on target to lose 1 lb a week.