Stomach fat is the most difficult one to reduce. Requires a lot of discipline. Do daily planks - start with one min plank - 5 times a day. Increase it to 2 min plan after two weeks - 5 times a day. Do it daily. Get to 3 min planks 5 times a day every day after the following two weeks. You need to spend 15 mins in your entire day. Secondly do stomach crunches - 50 a day and split it by 10 at a time. Get to 100 A day in 3 weeks and continue for rest of your life. You will see amazing difference in couple of months.
stop beer or fatty foods. If you are gym person, an hour of any exercise will keep you fit and active.