I think that being yourself and feeling good will negate most "negative" associations with what you're wearing. The only tips I have are ones that suit me specifically BUT I swear by the following:
I never wear eyeliner under the eye, only on top.
Converse are my favourite shoes - I'm in a band (yes, EVEN at 35 to the PP who thinks that your 20's is the only time you can wear Converse - we also, shock horror, played some major festivals last year - oh, the CRINGE) and they're perfect for jumping about on stage.
Colours are sort of important. I know that red suits me because I'm dark haired but like to experiment outside of that.
The biggest game changer for me is giving up foundation and spending whole weeks wearing no makeup. My skin has never ever been better. Past Medusa would be very jealous.
Wear clothes that fit you and feel good, rather than obsessing about what size you are. As a former anorexic who wasted five years of my twenties worrying about being a size six, it's the biggest regret I have. Thirties me has so much more fun.
It's OK to look in the mirror and see a shape that isn't reflected in "celebrity culture". I wanted to be a lithe, long legged model type with boobs but sort of got stuck at five four with a definite pear shape that not even Anorexia completely got rid of. My much longed for boobs are A cups. It's who we are, it's OK. Way more fun to be yourself.
Smile. Find the fun things in the everyday. That keeps most people looking and feeling younger and happier.
A good pair of dark coloured bootcut jeans will go a long way.
Style hack: I bought a "blazer dress" from Primark that I use as a long open blazer jacket. Looks great and it gets a lot of nice comments.
Jodie Whittaker is my "late thirties" style inspiraton.