torso is always the last part of the physique to really get all that toned, even if you do a million situps or crunches a day. diet is big, start doing cardio workouts till you have at least one heart attack. riding the bike is always a good way to start.
you can diet all you want, but if you want to see results that are long term and wont make you feel guilty if you eat ice cream twice a week you need to work out like you're training for a big race or something.
some ppl i know who've had success have chosen to run a 10K or even marathon at a specific date, like 3 months away. this "judgement day" always seems to be good motivation, plus you get to accomplish something really neat. nobody scoffs at anyone who runs a 10K or up no matter the time they run.