If you want to go all out and be ultra-glam Audrey Hepburn, you might want to try this look from Roman Holiday. Using Vintage Vogue V2239 (below), you can almost exactly recreate Princess Ann's ballgown. I actually bought this pattern for just that purpose, and though I haven't used it yet, all I'm going to do is eliminate the sash and attach a small bit of fabric crosswise on the bodice.
If you are going for a Sabrina look, there are two patterns worth looking at. 1) Vogue Easy Options V8020, is an oversimplified version of the cocktail dress shown to the left. It has a flared, pleated skirt and would look very cute in black (see picture below, left).
2) Retro Butterick '57 B4513, is a much closer copy of the Sabrina dress and my personal favourite. I've been wanting to make a copy of that dress for years, and this pattern is the closest copy I've ever found! See for yourself (below, right).
If you're going for a more dainty, Love in the Afternoon type look, there are a few options for you as well. 1) Vintage Vogue V2960 (below, left) has a deep, scooped neck, fitted bodice, and flared skirt that's quintessential 50s.
2) Vintage Vogue V2267 (below, center) is actually a pattern I own and bought just to be Audrey as Ariane in Love for Halloween one year. It's a very comfy dress, easy to make, with a light tulle underskirt to give the skirt more body without being cumbersome. And it has pockets!
3) Retro Butterick '52 B5032 (below, right) is more of an all-purpose 50s pattern, but still works because it's still in Audrey's line of style. Comes in a more fitted skirt or a wide, flared skirt.
If you're going for a very simple Holly dress, like a little black dress, then try these patterns out. Pretty much all of these would look good in any neutral colour or a soft brown tweed, so don't be afraid to experiment! 1) Vogue Easy Options V2218 (below, left) is actually a set of two-piece dress suits, but the one pictured fits together so well it's worth noting. A lot easier to sew, it's good for beginners and you can mix and match with your current wardrobe.
2) Very Easy Vogue 8282 (below, center left)a very nice sheath dress with matching simple jacket. Just forget about the lace appliqués and it's perfect.
3) Very Easy Vogue V8146 (below, center right) is very similar to the one just before, bit with a slightly more elaborate coat. Still a very easy to make sheath dress, if that's all you need from the pattern.
4) Burda Dress 3477 (below, right) is a sheath dress very similar to the one Audrey actually wears (right). If you were to add a tie sash to the waist and some fringe along the bottom, you'd have the dress exactly.
If you want to do more of a Holly Golightly suit, or know that it'll be pretty cold wherever you are and want a nice Audrey-style coat to go with your outfit, you may want to try Vogue Wardrobe V2988. It has a few dress options or separates, and the coat is fantastic (below). 
If you want a more generic little black dress that still very Holly Golightly, but you don't really care how accurate it is, here are a couple of options for you. 1) Simplicity New Look 6723 (below, left). Still very recognizable and very similar to some readymade dresses I recommended in the More Holly Golightly/Audrey Hepburn Costume Tips post. (Note: since I couldn't directly link to this pattern, you'll have to scroll about halfway down the page I could link to and click on the picture to see more information.)
2) Butterick Chetta B 3863 out of print (below, right). While this pattern is out of print, you can still buy it through Butterick's website. This dress is a very simple set with either a top and skirt or a one-piece dress.
And what would a Holly Golightly dress be without that giant, flying saucer of a hat? I searched through a lot of hat patterns before deciding that Butterick's B4472 (below) would be the best bet for you. It looks to be a lot easier than any of Vogue's patterns, especially the vintage ones, and by just switching the crown of hat A onto the brim of hat C, you have an exact replica of that iconic hat. Just throw on an ivory bit of fabric and you are Holly Golightly! 
So there's everything you need for Audrey's characters. If you'd like to dress more like Audrey herself did in everyday life, I've thought of that, too. Read on!
A trés chic dress suit is dressy, classy, and versatile. Very Easy Vogue V8319 (below) has a gorgeous pattern with a fitted sheath dress and classy, wide-yoked coat. It could also double as a Jackie O. costume in a pinch.
Skinny pants. I found two very good patterns for skinny pants, surprisingly. They were actually called cigarette pants (or trousers) in the day, and it does sound a bit classier and less spiteful than skinny, doesn't it? Anyway, these would be good for either a Funny Face beatnik type costume, or with a nice top it could be a flirty, casual 50s outfit. 1) Vogue V8330 (below, left) is a more modern pattern, but I like that it has three different lengths so you could have actual long pants, capris, or the cigarette trouser length depending on your preferences. This pattern must be made with a stretchy fabric!
2) McCall's M5273 (below, right) is more of a one-length pattern, but it's a little more classic in design with the flat front for a cleaner line.
A flirty little cocktail dress in any colour of your liking. Don't think Audrey limited herself to black! Feel free to experiment with Butterick B6582 (below). 
And, not to taunt you or anything, but if you ever come across this Holy Grail of Audrey Hepburn patterns, snatch it up! This Vogue pattern set came out in 2000 and wasn't out for very long, and it's extremely hard to find now. I'm guessing it didn't last long because it very closely copies Givenchy's designs for Breakfast at Tiffany's -- a little too closely, if you catch my drift. Check eBay once in a while for Vogue Wardrobe 2396 and you may luck out, though don't be surprised if you get caught in a bidding war. 
So there is everything ... for now. If there's anything that you think I missed or if you have questions about anything, please don't hesitate to contact me. I'd be more than happy to help.
Helpful hint: if you're going to buy a Vogue pattern, do it through their website! Unless they're out of print, they will always be on sale for up to 50% off.
