The first thing you should do is get some simple blood tests to make sure you don't have a medical issue keeping you from losing. Those could include hypothyroidism, insulin resistance and PCOS (if you aren't past menopause). These conditions can cause weight gain and/or make losing almost impossible.
The second thing you need to do is calculate the calories you actually need on a daily basis, then keep a food diary to see if you're staying within your calorie allotment.
Make sure you center your diet on protein and complex carbs (fiber), such as those found in veggies, whole gains, nuts, seeds, etc. Protein and fiber fill you up and keep you fuller longer. Of course, eliminate all sodas, candies, fast foods, etc.
Make sure you get exercise each day. Walking is excellent, as is yoga, zumba, dance or just about any other physical activity that will keep you moving.