What should I know before adopting a cat for the first time?

I’m going to be adopting a cat from our local shelter in the near future and I’m wondering if there are any pearls of wisdom you’d like to share with a first-time cat owner. While our family had cats growing up, it’s a bit different to get one on your own! Specifically, what items would you buy for your new cat (besides the obvious ones like food, a bed, and a litter box)? What other tips could you impart to a guy like me? Any recurring medical/hygienic concerns besides nail clipping/ear cleaning?