The people I most admire for their style aren’t those that follow every trend and dress in designer clothes from head to toe, but people like Sofia Coppola, Charlotte Gainsbourg, and Grace Coddington. These women are style icons not because they follow rules but because they make their own, and each have a strong sense of style and a clear signature look.
Anuschka Rees, German fashion blogger and author.
A sense of style is something that takes time. Time first to figure out what you like and what likes you. And then time to put looks together, learning and developing as one goes along. But it’s all fun, right?
Ms. Rees has a blog that talks all about this and she has a book, which I took a peek at last year. It’s very complete. Detailed and perhaps a little overwhelming but if taken a bit at a time it certainly has something to offer and it’s a good place to start for anyone who needs a little guidance.
As far as “rules” go I don’t think they’re such a bad thing. Rules can help, actually. Like the following:
Don’t mix prints. Don’t! Unless you know how to do it.
Don’t show your bra-straps. Come on! Showing bra-straps doesn’t look cool or sexy it just looks sloppy.
Spend money on investment pieces. My personal fave. Invest in expensive staples like a quality 100% cashmere sweater (from England or Italy), a wool blazer, a good fitting pair of trousers and/or a skirt. Choose classic silhouettes that will never go out of style. Less is more and much better for the environment.
OverDressed for Life 
I’ve never understood the appeal of bra straps showing. It is common, especially in women walking around in workout clothes. Once in a while I really have to work hard to keep my mouth shut about such outfits.. For example, “did you forget to put on a skirt?” or “have you seen that outfit in a mirror?” or “why are you wearing only your slip?”