Identify an overall theme for the fashion show. For instance, perhaps the styles being modeled relate to a select season, an upcoming holiday, or a specific venue (office, a beach, a cruise). Maybe the show is targeted to a certain age group (teens and tweens or women over 50). Perhaps the event showcases the versatility of an up and coming designer or reflects what a mix of different artists have created from a limited number of materials. Other options for a themed fashion show might spotlight a particular era ("Fab Finds from the 40's"), borrow scenes from popular films and TV shows, or celebrate cultural diversity with fashions from different regions of the world.
Determine how many models will be participating in the fashion show and whether they will only model one outfit each or have multiple wardrobe changes. The latter condition is crucial in terms of allowing enough time for them to change clothes backstage before they have to come back on again.
Instruct all of the models to put on the outfits they are going to wear so that you can determine the best order for them to appear in the show. In some cases, this decision may be out of your hands (the designer has specific transitions that he wants you to follow or perhaps the title of the event, "From Dawn to Dusk," doesn't allow any reshuffling). If it's not possible for the models to hang around while you physically move them from one slot to another in a lineup, the very least you should do is take a digital photo of each model so that you'll have something to work with on your computer.
Record each model's name as to how she would like to be introduced in the show. Get a thorough description of each outfit from the individual who designed it. This description needs to include the type of fabric and lining, the detailing (a faux fox collar), how it is accessorized (4-inch black patent stiletto heels, a Panama hat, jade bangle bracelets), and (unless it's completely obvious) where it might be worn ("perfect for a day at the racetrack"). If multiple designers are participating in the show, you will need to jot down their respective backgrounds, where they studied, what inspired their creations, and any other information they would like you to include. If the items being modeled are for sale, you will want to include the price of each of them in your commentary.
Allocate an equal amount of time for each outfit being modeled. If it's the first time you've ever done this, the word count for each description should be between 100 and 200 words. This is dependent, of course, upon the physical length of the runway or stage or whether they are strolling around a swimming pool or patio. Since you will likely have only one rehearsal with the models, the best way for you to test whether you have written too little or too much is to walk the runway or circle the pool yourself at a leisurely stroll and read your first description out loud. Whatever the word count for this first one, the rest of your write-ups should be about the same length.
Decide on music that will play beneath your commentary. Unless you can rely on the assistance of someone to handle the sound system, keep things simple. The music you select should be consistent with the overall theme of the show and should be played softly enough in the background so as not to drown you out.
Write an opening and a closing that supports the theme of the show. If it's a fund-raising event, for instance, your opening remarks will thank the audience for coming and explain that the proceeds of the show will go toward such-and-such. If you're highlighting the works of a particular designer, your opening would start out with her background, her accomplishments, and what inspired her to come up with the designs being featured. If the purpose of the show is to get people excited about the upcoming holidays or summer vacations, grab your audience's attention early with a clever quote, a statistic, or the reading of a short, topical poem. Closing comments will thank the audience, the models and the designers and let everyone know what's next on the agenda, where to adjourn for snacks, or announce where the clothes can be purchased.