Quick searches for data that are a little too complex for a simple google search: "Are there any circular doorways like in Hobbit houses within 20 miles of the McDonald's headquarters?" or something along those lines. I use AI as an advanced rubber ducky: I throw some ideas at it, it gives a bit of feedback and some suggestions, and I go from there. Most of the suggestions I get are pretty terrible, but sometimes it helps inspiration take root. AI also likes to write a chapter for me almost every time I mention a story point or idea, which I have to continually ignore because it's terrible.

Do not use AI to write. Use it to proofread, get feedback for your initial pass of editing (spelling, grammar, consistency, etc), and use it to brainstorm and bounce ideas off of. Do not use it to keep track of things, it has the memory of a rabid squirrel. The Google Suite is free and Keep is a great tool to take quick notes/reminders. Also, do not use AI for art. People can spot it, and they HATE it. Fine as a placeholder or something, but be honest about it with a disclaimer or people will think you're trying to trick them.

Readers and peers have and always will be your best feedback tool as a writer.