Best way to lose sizes...?

I was wondering if anyone had a good way to lose sizes (of clothing in case you were wondering ;) ). It's not my weight that bothers me so much as it is my size (12- 14, depending on if i've washed ithe jeans/top or if it's a good day), so was wondering if anyone had some good toning tips, esp for hips and gut (I always seem to have a little bulge!!!). Anyway, i'm hoping to get back to a size ten like I was a year ago (yes, I know i grow, but still... I'm sick and tired of blaming my shrinking clothes on the washing machine!!!).. thanks for your help!!!

Weight training and changing your body composition.  If you have hips and a gut, then you probably need to lose some fat as well.

Good plan. Weight is lame.
But some ppl will always be a size 12. I am sick and very skinny, but I can not fit into size 8 (Australian size 8. Its like "THE" size) because i simply am not build that way. I'm 167cm which isnt very tall. My BMi is super low tho. As long as I'm in proportion I am happy

The best way to lose sizes is to eat healthy and reduce cals. For speedy results, fidn your maintainence and minus 500 cals, but dont go under 1200cal. Also with eating healthy is exercise. If you're like me and love food, just eat about 1800 cals, but make sure if you're trying to eat 1300 cals you burn 500 off (thats why i like to exercse early. So if i do miss an exercise, I  just eat a little less)
Try and eat healthy foods. Unhealthy fake foods will make you bloat and be handled funny by the body. And I dont mean live on salads. Lean meat/protein is very impotrant as is carbs. if you find calorie reduce hard, jsut decreasr (dont cut out) the startchy carbs, like potato and pasta and rice. just have one per day. So have a sanwhich on thin wheat bread at lunch, or a wrap, and only have a few potatoes at dinner, or a little bit of pasta (or none) for the short term. Its not that carbs are bad, they're just the easiest for mnay people to cut out.

The problem is, no one knows what i'm trying to do-- i'm just trying to lose a size before I get any bigger. I can't just cut out loads of stuff at dinner, because my parents would start to wonder. is there a way to eat less during the day so I can just fill the gap normally at dinner?