Not too sure on the boots I tend to like slip on dress shoes
Lace-ups are much better than slip-ons. I don't know if slip-ons even qualify as dress shoes.
But yeah, nice shoes and button-up shirts are a must. Match your belt to your shoes (black & black, brown & brown). An adult male should NEVER be seen wearing running shoes except for when he's jogging, or at the gym.
A good place to start is to have one good pair of black dress shoes, one pair of brown dress shoes and a pair of good boots. You'll wear (require) the brown dress shoes the most as they are the go-to shoes for many, many looks.
Dark jeans are good to have too. No rips or stone-wash effects.
Above all - make sure your clothes FIT. Chances are, they'll be tighter than you're used to but you'll grow accustomed to it quickly and look much better for it. 75% of the men I see wear clothes that are too big for them because they would rather be "comfortable" than look good.
I could go on but there are entire websites dedicated to this kind of thing. Check out "Real Men, Real Style" for starters.
You're on the right track, for sure. ZZ Top were bang-on when they wrote "Sharp Dressed Man". It's no cliché - it's the truth.