It's always a bit harder for novels on visually-driven sites like Instagram, but you can make aesthetically pleasing graphics with a site like Canva to post, and they have different templates for various sites with exact dimensions.
like here's a quick look at some of my old designs. Each has a quote from my story.
Or if you'd like, you could commission artists to draw your characters or a scene and get their permission to post their work on your account.
And any time is a good time to start a Patreon. Never know when you snag a dedicated reader that wants to support you. They could be your one subscriber for all you know! Just have like one exclusive post done for each tier you offer and then don't make any new posts until you actually have a Patron.
As for what to offer: early-access pages, AU scenes, writing advice, process work, NSFW extras, etc.