In order -
1. Diet: Eat a calorie deficiet, but not too much. 20% under maintenance is a good start. Keep a food log.
2. Resistance Training: Lift heavy weights, as you want to keep as much muscle as possible.
3. HIIT if you can, otherwise cardio.
4. Persistance: Fat loss isn't linear. Some weeks you won't actually lose anything other weeks you'll surprise youself. Have a plan and stick with it. Don't get disheartened if you don't make progress initially or if you plateau. Try to evaluate what you are doing wrong.
5. Take measurements: The mirror can be decieving, don't trust it. Weigh yourself, measure your waste and get your BF% checked monthly.