Answer: a wall or out the window or something else. Those "everyone" probably never had a thought

everyone around me treated me like a weird freak for staring off at like a wall or out the window or something else

WTF? Almost everyone does this! Sounds like you grew up with assholes who were looking for any excuse to mock and berate you. In which case, I'm sorry.

If you were frequently getting lost in your thoughts and not responding to them when they'd try to get your attention then maybe I could see some light teasing.

One thing I would add, not because it's wrong to do this but because it might lead to people thinking it odd: if you are staring out of the same window or at the same wall for more than a few minutes, maybe switch your gaze to something else (a different wall or window or whatever). That way it doesn't draw as much attention and it's makes you look like you are more seated of your surroundings.

Stare directly at the people who are treating you like a freak for staring out the window.

Gazing out the window and zoning out are absolutely normal human behaviors.

Put them in a jar on your bedside table.

It isn't one place. Neurotypical eye movement is fairly constant, with a lot of time spent looking at or around other people. People who are autistic or have ADHD have a different pattern and often get commentary that they are staring at something like they want to burn it down or that they are off with the fairies.

To help with masking one strategy is to have a frequent face check, looking near the faces of people who are in the room, especially those who have just entered or moved. If someone is speaking they should be looked at but not 100% of the time, more like 70-90%. Other time should be spent looking around the room, looking at whatever is behind or around them, or at whatever they are presenting if applicable.

That said, if that isn't enough clarity I would recommend spending some time actually watching other people. You can do this in a classroom environment but people may find it disconcerting, so using sunglasses and doing it at a café is a fairly good option. Pay attention to where their eyes are going and what they are doing. If they are talking to someone compare their eye behaviour while they are talking to while they are listening, it is quite different. Same with if they are eating, drinking, reading, and so on. Some people spend a surprisingly large portion of the time while reading not looking at the page.

One reason assholes got mad about you doing that was probably because they wanted your attention on them in that moment. Everyone zones out and stares at nothing sometimes but some people are faster at snapping out of it. If the default position for your social engagement switch is "Ignore," you have a delay while you switch it to "Engage." Or they're better at hiding the fact that they're bored with the person who's been talking to them. Meanwhile the asshole is already all focused on "Me! Me!"

Gazing at the bridge of their nose might help

I keep them in my eye sockets

In a glass of water, on a table next to your bed.

I just roll'em until people get the idea.

Roll them into the back of your head and practice throat singing, it helps with the thinking. Note this also gets you out of having to go to church, they'll bring the priest to you.

Autism screening.

All those people that treated you as "weird" for this do it themselves as well. If you were gaining special attention for this in particular such that multiple people noticed and weren't just messing with you, then it's probably not the fact of your blank staring itself, but the length of time. Normal steady gaze at nothing in particular for periods is normal and people only perceive it as staring when it's reached some threshold length of time.

Why you specifically might be doing this past that threshold I couldn't tell you. Many are suggesting ADHD or Autism, could well be but otherwise maybe you're just finding yourself easily distracted or prefer longer trips into your own head. If you worry about it, best suggestion is just to randomize your gaze periodically in response to stimuli in the room, but the thing is if you're not already doing that automatically it's probably because you're too engrossed in thought for that stimuli to get through.

Have you never heard the phrase “staring off into space”? It’s a very common thing. As long as you’re not staring directly at someone (which can come across as creepy), it’s just something people do.