Eat in a calorie deficit, weight training and eat lots of protein as this will keep you fuller for longer and it will help you retain and build muscle mass. Aim for 1.5-2x per kilogram of bodyweight in protein.
As long as you're in a calorie deficit, you will lose weight. I would only recommend being in a deficit in cycles though (8-12 weeks max) as you need time at maintenance to get your metabolism kickstarted again.
Increase your training intensity as well both cardio and weights wise. You could try HIIT training, circuits etc.
Use the MyFitnessPal app to track your nutrition as well.