Mo, I see what you mean about outfit #1. There's nothing too revealing about it, but it's definitely more girlish than outfit #2. It sounds like you and I are on the same page when it comes to recent fashion choices. I'm edging away from "cute and a little scruffy" and trying to achieve "chic and poised". Whether or not I succeed is up for debate, though...especially the scruffy part....sadly I'm not one of those women who still looks polished by 5 p.m., no matter how hard I try.
TeeandCee -- what you said about it being too youthful if you can't figure out how to put it on made me laugh out loud!
GP, I know what you mean about the short shorts. I'd still wear them, because let's face it, short shorts aren't, in fact, all that short on me -- but I do have thoughts of "will I look silly or chic in this?" these days. My figure hasn't changed much since I was a teenager, but I don't want people to mistake me for one from the back!
So to answer your question, I don't have a huge list of don'ts, but there are some things I wear differently now. Like graphic tee shirts -- if I wear one, I don't wear it with torn jeans and flip flops. I don't wear flip flops so much anymore either, unless it's somewhere very casual, like the park or the beach. I bought a pair of UGGs three years ago because I think they're cute and omg they are SO comfy, but I only wore them outside once, and felt ridiculous. So I keep them for what they are meant for: use as house slippers. If I'm doing a particularly disheveled hairstyle, I don't wear scruffy clothes that day; I wear something more polished. I still wear short skirts, but if my legs are bare, I have to pair the skirt with tall boots or I feel naked.
There are also things I do now that I wouldn't have five years ago. I buy more fitted clothing, and I pay a LOT more attention to achieving a good fit, even for looser items. I wear high heels with knee-length skirts. I never used to do this. Now I wear high heels whenever it's possible and appropriate. It just feels good -- more "grown up" -- but I had no interest in high heels in my 20s and even early 30s. I wear skirts and casual dresses a lot more. I wear fewer stretchy knit tops and more structured woven ones. I've developed a keen interest in good quality coats and shoes. There are probably more things, but that's what I can think of off the top of my head. I guess my main goal is not not look too girlish. I'm ready for people to call me Ma'am at the grocery store!