Peh, going out on the runway in that! If you want to be the next top fashionista, you're going to need a lot of help.
Lets start with the basics. First things first, go through the tutorial to learn about the interface. Now you can start making outfits, which is pretty easy. For the most part it's self explanatory, brown boots can go with western and paint-splotched pants can go with hippie. Now that you know how to make outfits, you just need to know how to get bonus points and how to utilize your time.
Signature outfits are not optimal. If you want to unlock them for dress-up mode, I suggest doing it after passing the level.
Sometimes, dresses will appear on the left side of the screen. When matched with the correct style, they give a decent amount of points and are fast, so I would recommend them if you need to hurry.
Bonus Specials: Sometimes, getting a certain score on a model entitles you to a special. Try to use your specials because if you have 5 and earn another special it is wasted and there is no bonus for leftover specials at the end of the level.
Bonus Points
Quick modeling and same category in a row. When possible try to send all three models out in a row and have chains of styles. To do this you need to have your thinking brain on in addition to that creative brain. For instance, if you have a hippie model and two western models, dress them all then send out the hippie followed my the western girls. Doing this will give you a succession bonus as well as a X2 western combo with the possibility of a growing combo.
Accessories. Accessories can provide a nice bonus to any outfit but will do more good when they are placed with a matching style. Although a +50 bonus is nice, a +300 is better. Also accessories really don't hurt you so try to use any left on the last model because a +150 (for 3 non-matching accessories) at the least is still good to have.
Those Fashion Rules. When you send out a model following one of them, you will get a bonus in the 50-300 range. Not every model is going to have one, but try to capitalize on it when you can.
Now go strut your stuff!