Juicy Couture Blazer, $198 Photo: shopbop.com

No matter how closely you watch what you eat or how hard you hit the gym, it's always nice to know you have that outfit in your closet that will make you look 5 or 10 pounds thinner. Fortunately, there are several trends this fall that do just that!

Now, of course, all the old standbys still apply. Darker colors like black, dark gray or navy are slimming, and wearing something that fits, even if you don't like the size on the label, will be far more flattering to your figure than something that's too tight or too baggy. And remember, shapewear isn't just for the red carpet. It's easy to wear and it works.

But that's not what we're talking about today. Here are the three hot trends that will have friends asking what diet you're on!

Tailored jackets and blazers. Thanks, in part, to "Gossip Girl," tailored jackets are huge for fall. You can go preppy, with an embroidered crest, basic in navy or beige, or play up your inner-bad girl with black leather. The most important thing is that it's tailored to fit you properly, so the arms should be slim (but not tight), and the waist should nip in to show your shape. Be careful, though, if you're busty -- a jacket that buttons in the wrong place (either too low or too high) can make you appear top-heavy.

Virginia Johnson Scarf, $198 Photo: shopbop.com

Wide, cinched belts. Speaking of nipping in at the waist, a great belt will help show off your womanly curves (or, for some folks, help create them). Plus, it's a great way to add some color and excitement to your outfit. Belt a dress, a cardigan, even a jacket or sweater -- there are no rules.

Scarves and hardware. One of the best tricks ever when it comes to dressing yourself slim is distraction. You're a pretty girl, and a great way to help highlight your face is with an amazing scarf or a big, funky necklace. It draws the eye up, up and away from any problem areas (waist, thighs, etc.) and puts the focus on you. Wear a lightweight silk one while it's hot, and once it cools down, switch over to cashmere or wool.

Want to know more about the biggest trends this fall? See what's on trend for beauty over at StyleList!