I have my movement keys shifted right by one key to ESDF. Quickbar hotkeys are arranged clockwise around that, on ZAQ123456TGB. This gives me easy access to 12 hotkeys without having to stray far from the movement keys. First quickbar uses plain keys, second uses Ctrl as modifier. Additionally I have four slots bound to the side buttons of my mouse (two buttons with and without Ctrl) for a total of 28 slots. So far I haven't needed more, though I haven't gotten into the really hard content yet.

I use camera-relative movement because then I don't have to keep track which way my character is facing. I also use a gamepad for more relaxed content and it's easier to have keyboard movement work the same way. Mouse is mostly reserved for rotating the camera, selecting enemies and ground targeting, but I occasionally use it for selecting party members lower down on the list (F5-F8 are harder to reach than F1-F4) or in other alliance groups. A few skills I have in click-only slots because they're not critical to use quickly in combat (protect, summons etc).

My WHM setup has single heals on 1-5 (cure, cure2, cure3, regen, tetra), plenary on 6, AoE heals on Ctrl+1-4 (medica, medica2, asylum, assize), benison on 5, attacks on TGB (aero2, stone, holy) and Ctrl+T (aero3), various buffs on ZAQ (presence, largesse, esuna) and Ctrl+Q (thin air). I'm pretty sure Ctrl+GB have something too but without opening the game I'm not sure what. Possibly fluid aura and repose. Mouse buttons have benediction, lucid dreaming, swiftcast and raise. A few skills are arranged a bit illogically, largely because I'm relatively new to Lv70 content where they can actually be used.

I've mostly healed on WHM recently so my memory is a bit fuzzy on what my SCH and AST setups look like. AST is pretty similar to WHM in that heals are divided between single-target and AoE and attacks are in the right block. SCH has heals on 1-6, attacks on Ctrl+1-6 and some mixture of buffs and utilities in the remaining keys.