Katie Cassidy Hairstyle

Try something different for a shoulder-grazing bob by giving it edgy piecey waves at the ends a la Ashley Olsen. This style is supposed to have a casual feel, so don't worry about getting the waves perfect

Get her look: Add a texturizer to towel-dried hair. Gather hair back into a ponytail, twist, and secure with an elastic. Remove elastic when hair is dry, and gently run fingers through hair to separate waves.

The Olsen twins may sport the same basic layered cut, but just by styling differently you get two different looks. Mary-Kate (left) opts for messy waves while Ashley keeps her mane straight and simple. The twins are at Barnes & Noble in New York for the launch of their new coffee-table book "Influence", which details their fashion inspirations.

Create Mary-Kate's bedhead look: Blow-dry shampooed hair until it's 80% dry, then work in mousse. Twist hair up in a high bun and sleep in it overnight. In the morning, release hair and style as needed.

Katie Cassidy Hairstyle

Girly braids exude a kind of grown-up sexy appeal when you combine them with sensual, voluminous waves like Ashley Greene.

Get her look: Make a side part and braid a small section of hair along the hair line and secure it with a clear elastic or bobby pin. For long-lasting curls, first spritz sections with hairspray, then wrap hair around a large-barrel curling iron.

A half-up keeps things cool and girly in summer! We love Ashley Greene's extra-romantic half-up that is pretty enough to wear to a wedding party or a big date.

Get her look: Blow-dry hair using a large round brush, wrapping sections around the brush and blast with hot air to create soft waves. Pull hair at the sides back into a half-up and secure with bobby pins or a pretty clip.

When you've got statement earrings and/or gorgeous makeup like Ashley Greene's, an understated pulled-back style lets you show them off. For a timeless look, try the "Twilight" star's low textured chignon.

Get her look: Add texture by curling hair using a large curling iron. Pull hair back, twist into a low bun and secure with bobby pins. Spray hairspray all over for extra hold.

An elegant half-up gets a dose of glamor and feminine appeal with soft waves. Try Ashley Greene's romantic 'do, which has extra height at the crown and visually elongates a round or square-shaped face.

Get her look: Curl hair using a curling iron and tease the crown to create the volume. Pull hair from the front and sides back, letting bangs fall out, twist and secure with bobby pins. With the palm of your hand, push the hair up from the back to add height at the crown. Style bangs to one side, and finish with hairspray all over.

Looking for a hairstyle that portrays effortless elegance? Try a sleek chin-length bob. Ashley Greene wears hers with a long side-swept fringe, which flatters all face shapes.

Get her look: Spritz styling water onto damp hair and blow-dry with a flat brush, rolling under at the ends to achieve the roundness in this 'do. Create a zigzag side part, and push hair behind one ear.

Katie Cassidy Hairstyle

Anne Hathaway is sweetness personified with her messy-in-a-cute-way 60s' ponytail and geeky glasses. Who says a low-maintenance look can't be chic?

Get her look: A day-old hair works best -- spritz hair with beach spray and scrunch hair with a diffuser to add texture. Then pull hair back into a high ponytail, leaving face-framing pieces down around the face

The trick to touchably sexy waves is shine and body a la Anne Hathaway's beautiful mane. To coax volume and shine, consider investing in a mixed-bristle brush, and brush through strands as you style.

Get her look: Make a middle part and blow-dry hair straight. Take a large-barrel curling iron and curl sections away from your face. Finish with a mist of shine spray.

"Bride Wars" star Anne Hathaway does a modern take on the '50s flipped 'do, complete with teased height and a satin hairband at the New York City premiere.

Get her look: Straighten hair using a flat iron. To create the flipped ends, blow-dry using a small round brush -- curl ends outward and set the style with a blast of cool air before releasing. Add height by teasing roots at the crown, then slip on a sleek hairband.

Katie Cassidy Hairstyle

"The Ex " star Amanda Peet looks stunning in blunt soft bangs and shoulder-length layers .

Get her look: Spritz volumizing spray on wet hair. Blow-dry the bangs first, using a vent brush to avoid a too-puffy look and pointing the nozzle of the dryer down. Blow-dry the rest of the hair, using a round brush tolift hair away from scalp to create volume.

Who: Angelina Jolie
Where: "Kung Fu Panda 2" Los Angeles Premiere

Channel Angelina Jolie's effortlessly glam look with a simple ponytail that can take you from work to play. The beauty of this look? It doesn't have to be perfect and it's accomplished in under 5 minutes!

Get her look: Work with a day-old hair -- curl the ends of front sections using a large curling iron then gather the rest of the hair back into a high ponytail and secure with a black elastic.

A half-up is easy to style and versatile for all kinds of occasion. Add a little drama to your look by back-combing the crown area a la Angelina Jolie for added height on top.

Get her look: Spritz volumizing spray at the crown area then back-brush the roots to add volume. Spray more spray then smooth back the surface. Brush the sides up and back and secure with pins.

A color job is an easy way to update your look without a dramatic hair cut -- Take a cue from Angelina Jolie, who lightens her dark locks to light brown. Warm brown tones -- like Jolie's -- and rich auburns flatter most skin tones.

Get her look: To re-create the barely-there waves, spritz large sections of hair with beach spray and blow-dry with a large round brush, wrapping each section around the brush. Wait for hair to cool and set, then gently unwrap the section from the brush.