I would say do your intense exercise in the morning before you have breakfast. I know some people say "eat your breakfast first" for the energy but I find that I have to do it first thing in the morning or else I'll make an excuse not to do it. I would do some light exercise in the evenings like walking or yoga, it won't burn that much calories but it'll get you out of the house so you won't have time to think of junk food. If you have a personal organiser, put the exercise time in like it was an appointment in advance.
I would also plan your meals in advance. I found making one new recipe a good way to motivate me to learn how to cook and try out new foods. I would also stock some herbs and spices in your cupboard to flavour up your food-some garlic, ginger, lemon, basil and chilli are great for example. You can get a nice bit of fresh fish from your fishmonger, even the frozen fish will do although its not as nice admittedly and stick some lemon and dill on it and bake in the oven for 30 min and serve with some steamed veg.
You need to reward yourself for your efforts and have little non-food treats each week to incentivise you to continue e.g. pamper yourself. I would advise you to give yourself a bigger treat when you reach each 5lb weight loss and your eventual goal weight too e.g. a nice top in smaller size etc.
Give yourself praise when you do something towards being healthy-e.g. drink water, have a healthy meal. Say to yourself "I did well there, I had a healthy meal, I drank water" etc. It's important to have positive self-talk and to believe that you can reach your goal.
I would also advise you to take your measurements and notice how your energy levels increase as well keep track of weight loss.
If you slip and eat something unhealthy, don't dwell on it. Instead, get back on track straight away.
You're probably craving junk food now however the cravings will pass in about a week provided you eat unprocessed food, made from scratch-nothing sugary. It would be good for you to post what you're currently eating now so we can see what needs to be tweaked. In the meantime, I saw this little acronym online called "the 4 D's" which helps with cravings:
When you get a craving:
1. Delay-say to yourself "I'll have a biscuit/whatever it is later on". Cravings only last a few minutes so your craving will have passed by then
2. Distract- do something else (anything, aside from eating). Examples would be call a friend, relax, clean the house etc
3. Deep breath 20 times-a lot of the time we crave food because we're stressed out so taking a deep breath 20 times forces us to slow down. When we're stressed, our breathing goes shallow so taking a few deep breathes calms our body down again. Once you slow down a bit, you might realise "hey, I'm ok now, I don't need that biscuit/whatever".
4. Drink of water-to replace the food. It's also something for your mouth and hands to do.
For a flat tummy, I would cut out salt and alcohol from your diet, wheat too if you can hack it. Drink lots of water, herbal teas. Hot water and lemon is good. Exercise wise, do some cardio-like walking/running and some resistance training-like pilates/yoga etc.