Fireborn has a very good speedrunning tutorial on Youtube. I would highly suggest checking his videos out. It is an older Any% run and is only for 1.2.2.1 but is definitely a great tutorial to check out. That's how I started my Any% runs.

I'm not much of a current patch runner, tried it twice maybe. But what works for 1.2.2.1 for me is watching the guides from both fireborn and Gwonkee. Very useful guides especially for new runners. Another thing that can really help is watching the top runners. There's usually things you can pick up and learn from their runs

You can use OBS or whatever recording software you use to ignore certain colours when recording. Its a filter called "colour key" on OBS. This can be applied to specific programs that you are recording, such as livesplit.