Mechanical Keyboards

Go to a meet up if you can and try out different boards, switches, key cap profiles, talk to owners etc. before you spend any significant sums. Impact of key cap profile and materials is often underrated.

If you cant then switch testers and "cheap" 3d printed or acrylic boards are a decent way to try different layouts, especially if you can sell them once you finished with them. Sure you can skip this step if you know the exact layout you want, but I didn't.

Learn what types of switches you prefer, if you like them lubed, filmed, ball bearing mod, stem swapped, etc. is worth the effort. As is getting good at stabs.

I think another fundamental is deciding if you are one and done or you will keep buying boards. Buying keyboards then building them is the hobby for me, I have loads, more than 50. If its the former then you want to spend longer nailing down what you want, the latter it doesn't matter so much.

Its snobby but mass market boards are ok, just ok. I would much rather have something more premium, with a bit more thought around it. It is more risk than buying from your average shop though, and you need to do proper research into the GB runner, even then they can exit scam (ask me how I know).

Being able to decide everything you want for a board, mounting style, plate material (or even no plate), switches, how they lubed, if they filmed, what stabs you use, what keycaps, all make fundamental differences to a boards sound and behavior. Getting that how you want it can take time.