Works best on: Medium-length or long hair of any texture
Hairstyle how-to: Step 1: Wash hair and let it air-dry.
Step 2: Pull hair into a low, slightly loose, pony, just above the nape of the neck.
Step 3: Take one inch sections of the pony and smooth each of them with finishing cream or shine serum. Twist each section and pin it into place around the pony, twisting pieces around each other to create the knot look you see on Klum.
Step 4: Finish by smoothing finishing cream over the top of hair.

Works best on: Any hair length or texture (but you'll need two faux hair pieces, a bun, like Easihair Elegance Hairpieces, and a braided piece, like Easihair Serenity Hairpieces)
Hairstyle how-to: Step 1: Use a gel or pomade to slick hair back into a super tight high bun. Use an old toothbrush with gel on it to slick every tiny hair back.
Step 2: Attach the dome/bun hairpiece on top of your bun, then wrap the braided hairpiece around it.
Step 3: Use finishing cream or pomade to give hair a final polish and keep flyaways in check.

Works best on: Medium-length or longer hair of any texture
Hairstyle how-to: Step 1: Let hair air-dry so you can keep its natural texture.
Step 2: Pull hair into a high pony at the crown of your head. Leave a few wisps of hair hanging around your face and ears.
Step 3: Take one-inch sections of the pony, tease each one, then twist and pin into a bun shape around the pony.
Step 4: Attach floral accessories (or fresh flowers) around the bun.

Works best on: Long, curly hair (or straight hair that has been curled all over)
Hairstyle how-to: Step 1: Use a large curling iron all over to define curls (or create them if hair is straight).
Step 2: Divide hair into three sections horizontally and clip the top two sections out of the way. Take each curl in the bottom section, tease it for volume, twist and pin it at the nape of your neck.
Step 3: Repeat the tease, twist and pin routine (pinning at the roots) for all the curls in each section, working upwards. But do leave a few small face-framing sections hanging. Remember, this is supposed to look a little messy and imperfect.

Bonus tip: Aim to make the final updo bigger than you want -- you can always pin down any sections that are too large (it's easier than trying to add volume later).
Step 4: Curl the hanging face-framing pieces with a curling iron.
Step 5: Smooth bangs out (if you have them) with a round brush and mist with hairspray to finish.

Works best on: Any length and texture (you will need a curly ponytail hairpiece, like PutOnPieces Put On Ponys Bounce, to get a full bun like Beckinsale's)
Hairstyle how-to: Step 1: Use a round boar-bristle brush to smooth hair while blow-drying.
Step 2: Brush hair back into a high pony, keeping some volume at the top.
Step 3: Use a curling iron to curl small (one-inch) sections of hair in the pony.
Step 4: Attach the ponytail hairpiece to the base of your pony.
Step 5: Twist and pin the tail to form a large bun in the back of your head.
Step 6: To finish, take an old powder brush, spritz with hairspray and lightly brush over your hair to gently control flyaways.