The easiest option is to use your operating system's default browser, and turn on assistance. So on mac use Safari and turn on Voiceover, and on Windows use edge and turn on Narrator.

To really test yourself, once you have learnt the basics of using voiceover and narrator, turn off your monitor and navigate your website :)

In my limited experience, many people use one of those two options (the situation in Linux is unfortunately much less functional).

Yes! It's not even that much of a time investment; a short video [1] and some playing around can already give you a pretty good grip of common issues in 15 minutes.

Yes, that's not enough for properly evaluating the performance of what you're working on (screen readers differ far more than browsers do, and there's many different ways of navigating), but it helps form a mental model and to quickly encouter really egregious issues that e.g. make your entire project inaccessible with any screen reader.

[1] I think I used this one, to learn the general principles and to at least find the terms needed to find the shortcuts for my operating system: https://www.youtube.com/watch?v=5R-6WvAihms

There's no "learn how to use," just enable it on your existing devices. Settings > Accessibility on android, at least.

Consider making a habit of using it when you are circumstantially visually disabled: in bright sunlight, while you can't be physically present at the phone (eg while doing dishes or folding laundry), etc.

Absolutely worth it. Has helped me a lot, finding small issues like buttons with no meaningful label or custom checkboxes that don't announce their state.

I don't know what platform you're on, but I use VoiceOver on Mac. My blind relative uses JAWS on Windows.

If you are on Linux, give a try to Orca. It integrates nicely with KDE/Plasma and Gnome... and the browsers (Firefox, Chromium, Edge...)

I have considered writing a guide to using Voiceover for sighted users as a power tool, because it is great. The other ones not so much. The main problem you will find if you are developing is you cannot expect stuff that works in one screenreader browser combo to work reliably in others so you need to do a lot of testing with different combinations.

It would take a long time to get "up to speed" (setting the speech rate to 2x or 4x like a real user) but a lot of them have modes that show the spoken text on screen. That should let you test some basic a11y features like the "skip to main content" links.