The older I get, the higher my tolerance becomes for "conventional" looks. I think this mostly has to do with feeling like I've moved beyond the phase where I need to "play" with my own look everyday, and really just want to be able to get dressed without putting too much thought into it.
I remember in late high school or early college having something of an epiphany where I realized that all of us "alternative/indie" girls, wearing some variation on ripped stockings and combat boots, etc, had created a "conventional" form of dressing that just stood alongside mainstream convention, like a parenthetical comment.
I looked at all of the subcultures with which I loosely identified, and just no longer felt compelled to keep looking like everyone else around me -- the irony of all the effort it takes to "fit in" with the outsiders. So I started thinking really hard about how to dress *like myself* and not just according to formula. And I think it's actually quite difficult to dress cohesively and "have style" so to speak without using any reference points/conventions whatsoever, so it becomes a game of cherry-picking. Which conventions feel right, and which ones don't? How do you play with and manipulate conventions to suit your own personality?
For example, the newish "long-over-lean" convention, with fluid tops and skinny bottoms, has been a hard one for me to embrace. Try as I might, I don't feel like myself in skinny jeans, or in long fluid tops. I've enjoyed playing around with the look, but it's not one I'll invest heavily in. Same goes for, say, fit-n-flare dresses. Yes, I have a defined waist/hip that theoretically looks good in a tea dress, but when I wear them I don't look like *me* no matter how conventionally flattering they may be to my physical person.
And of course, it's important to distinguish between social conventions (e.g. black at funerals) and flattery conventions (lengthen legs, define waist, etc) -- and also to identify the places where the two converge (bras are a prime example of this), which can be the hardest ones of all to avoid/reject.