I've been training for over 6 years now (started out due to playing national level basketball). This is just the kind of thing that you don't want to do if some sort of six-pack is your goal.
Although genetics plays a fair part in it all (mainly linked to your metabolism) anybody can get fair results if they follow some simple rules:
Train with weights 3-4 times a week
Eat sensibly (and intake plenty of water)
Train your abs like any other muscle group (1-2 a week with weights)
Crash dieting will NOT do anything but make you lose musle and glycogen making you look thin (not in a good way unless you are into Dior), flat and shapeless.
Find your avg daily calorie intake at which you maintain weight and reduce it by 500cals a day. 3500cals = 1lb of fat, therefore 1lb loss of fat a week. Anymore than 2lbs a week is not good.
If you are new to training with weights you are lucky in that you can see both muscle gain and fat loss (to some extent) and experience pretty rapid gains.
That said, real results only come from years of training and eating sensibly. You don't have to be obsessive, just all things in moderation. I train 3 times a week (abs once a week) and have gone from 6'2"@10st to 6'2"@14st all while keeping a low bodyfat. This is me just in from work:
Nothing special, just in relatively good shape whilst still enjoying burgers and beer whenever I want. Or course, if and when I go on holiday, I focus on fat loss and really define things, but otherwise I am never actually dieting.
You don't have to be gay or anything. I just kept training due to my competitive sports in the past.
I applaud anyone who wants to simply look after their body.