The advice I've read, and the way I have proceeded, is to have patreon rewards be things you're already making anyway.
You know what I was already doing? Keeping a buffer. Bam, early access. I even specify that the early access is just whatever I can manage, I don't promise a certain amount per month- often I have a month where I can drop 8 pages, and then I have a month where I manage very little. i also drop pages in bundles of 4, so even though they're not really getting much "faster" they can read the group of four instead of waiting for one page a week.
And that's really the only draw. I drop WIP of the comic once in a while, mostly if I feel behind to show I'm working on it, any sort of cover art or promotional art gets popped on patreon first, and the occasional bit of personal art.
Promoting patreon is pretty easy since Tapas has a space for an advertisement under your comic, and webtoons allows an embedded link somewhere.
My experience has been that my patrons mostly just want to support me, and whatever perks that comes with are gravy.
I think it can help to be explicit on your patreon that you appreciate support, and will offer X, but want to avoid feeling pressured to keep up a specific regime, and so rewards may fluctuate. Doesn't erase that internal pressure, but it helps.