I really want to lose weight and get a flat toned stomach, but don't really know the best (and most quick!) way to do it.
I'm 17 and just done my A-levels, so have all this summer before I go to uni and want to look good! I've joined a gym, but what's the best kind of exercises I should be doing, and for how long, and how often?

Bodybuilders have a saying "Abs are built in the kitchen, not the gym." You can't spot exercise your way to flat abs. You already have a six pack, it's just hidden under a layer of fat, and the best way to show it off is to fine tune your diet to strip off the excess bodyfat.

Cut out all the junk food and white carbs, eat plenty of quality protein, healthy fats, fruit and veg.

In the gym, work your whole body, using compound lifts like squat, deadlift, bench press, pull-ups, dips, etc. When you are doing your cardio, go hard at it. The fat burning zone is a myth. If you work hard, pant and sweat, you'll burn a lot more calories, including more fat calories, than if you just stroll for an hour.

Crunches and obliques every morning will help too.

Running works wonders for my abs.

For some reason, other exercises just aren't as effective for me as far as helping me with that area, though.

But like someone posted above, it's best to have overall fitness and health, rather just try to get one area healthy.

Work the abdominals and the torso with machines at the gym they do wonders too.

Abs require a lot of exercises to work them out, because they are composed of many muscles. You have to hit them from all angles.

Here's a free guide on how to get abs, which has some good routines for getting a 6-pack