If you want to lose weight, the best combination to make consistent progress is focus on:
Calorie deficit is important as you need to be using up more calories than you are taking in. In order to accomplish this prioritize three things: amount calories you are taking in, control your portion size and increase your steps (e.g. amount of walking you are doing).
Strength training is very important to retain muscle mass and tone. Using a personal trainer 2-3 times a week could really help you. They will show you the right weight exercises to do in a safe and consistent manner, and enable you to progress over time.
The third critical component that is often overlooked is Lifestyle. A key element here is sleep/ rest. You should be aiming for 7–9 quality hours per night. Keeping stress and alcohol low is also vital to accomplishing your weight loss goal. Normally if we are under more stress, or drinking more, we eat more, and often tend to snack more too.
Focusing on the trifecta of calorie deficit, strength training and lifestyle will enable you to make the most progress and sustain the improvements over time. A Personal Trainer will help you accomplish all of this.