What are some tips/tricks you wish you knew or could give as advice to those of us about to dive into the world of home aquariums?

Any advice would be extremely appreciated! I’ve always loved aquariums and terrariums and used to have some decent setups with my dad and now it’s 10 years later and I’m itching to dive back in but have no clue where to start! I’ve been browsing thru fb marketplace hoping to find a hand me down tank. Impulsively I want to get a 40/50 gal tank and full send it but I feel like I should probablyyyy not get ahead of myself and wade back in with some more reasonably sized tanks so I’m currently in the process of gathering info so I can get started aquascaping and getting water cycling asap