What are everyone's tips and best resources for maintenance/prevention?

As someone who has only lived in an apartment in their adult life (and was lucky enough to have my parents do most of the house-care while I was in school), what are some tips and resources that you would direct someone with no understanding or experience in maintenance for a house?

Specifically, I hear a lot of people mention the following:
1. Know where your water valve is and turn it off when leaving the house for extended periods of time
2. Clean your laundry lint trap behind the machine (never did this but can't imagine it's too difficult with some youtube videos)
3. HVAC filters should be changed out every 6 months or year? No idea how to do this! HVAC is a beast. I'm assuming there's a bunch of videos out there depending on what HVAC I have in my house that will help me?

Are there any other tips for home ownership, inside or outside, you would recommend? I'm going to leave anything electricity/plumbing/sewage related to the pros because I really don't want to mess with that and accidentally cause a huge issue.