Greene's criss-cross hairstyle might look complicated, but don't worry -- you'll be able to achieve it in under five minutes. Give yourself a side part and sweep your bangs to the side. Take one thin piece of hair and twist it, securing it to the back of your head with bobby pins once it's finished. Do the same with several more sections of hair -- and pin them on top of the previous strands, angling each in a slightly different direction. Once the multiple twists reach the back of your head, wrap the ends together with the rest of your hair into a bun.

Adding a twist to an otherwise simple messy ponytail kicks it up a notch. Gellar's hairstyle only takes an extra minute -- before gathering hair up into a ponytail, take a strand of hair near the top of your head and twist it loosely, adding a thin section of hair every time you twist. Once it reaches your ear, pin it back and tie your hair up into a messy ponytail. Leave out a few wisps of hair to add to the overall look.

Portman's classy one-sided twist works well for those with thick or curly hair. To get this look, take a large strand of hair from the front of your face and pull it towards the back of your head. Start twisting several inches away from your face and tuck the twist under the hair at the back of your head, under your crown, securing it with bobby pins. Finish the look by applying smoothing cream to tame frizzy fly-aways (try TIGI Bed Head After-Party Smoothing Cream, $14.99).

The single-side twist (or braid) is Conrad's specialty. To get this look, first smooth down hair with a frizz-fighting cream (try Pantene Pro-V Smoothing Frizz Defense Cr�me, $5.99). Now grab a strand of hair and twist it tightly several times before pinning it down. Be sure to tuck the remainder of the strand under the rest of your hair to cover up the ends.

Tisdale's twist adds flair and volume to her side ponytail, and works best with long hair. To get this look, create a side part and then split the hair on one side into two large strands. Apply volumizing foam (try TreSemme 24 Hour Body Foaming Mousse, $5.50) to the front half of the split. Now twist your hair loosely, pulling it back. Once the twist reaches the nape of your neck, gather the rest of your hair and tie it into a low, side ponytail. Finish the look by taking a strand of hair at the base of your ponytail and wrap it around the elastic.