Aine: The moat common way to recieve ARCs is by constantly reading and reviewing books, normally in one genre. You need to make trustworthy and honest reviews. You will need to get yourself well known, by starting a blog or youtube channel. You can also sign up to different publishing companies, such as Penguin Randomhouse. You can make it clear on your blog or youtube channel that you may or may not accept self published books as ARCs as well.
Hope this helped! 🙂