Two questions, if I may etheltbags
1What do you mean by "smart"
2 Do you want to look like that?
Princess Eugenie fascinators aside, most "slebs "look pretty silly especially if you realise how much they have to spend and the people they have to "advise" them.
On the other hand, it would not be hard to adapt your own style as you describe it.
Ditch the holey leggings, treat yourself to a couple of pairs (look at M&S jeggings, also Sainsbury's, they are good value) Holes in jeans or leggings do not look good even on under 50's.
Lose the mini skirt. Harsh, but true. (I assume you wear the leggings UNDER it not OVER?) A long big sweater or tunic will look much better and be easy to wear. If you don't want to faff around with scarves, don't, but they can jazz up an outfit. Keep your DMs if you like them, but consider a pair of ankle boots (suede doesn't need cleaning!)
A rain jacket or duffle coat (or if you feel brave enough) a poncho on top and a backpack or crossbody bag and you could go anywhere!