Sharpie Ultra Fine point pens are good because the ink doesn't fade over time very much and it's doesn't smear if your hands are sweaty.
I use all caps lettering I learned from a cartooning book Ken Muse of Tom and Jerry fame wrote. If you look at well drawn cartoons like Peanuts that's the lettering I'm talking about. They use all caps because lower case sticks below the line. They also use the concept of kerning where all the letters are slightly interconnected, not just end on end.
I used to buy rolls of white 3m labelling tape from Markertek but I haven't seen it for a long time. It's bright white with a hard plate finish and looks a lot better than the masking tape I've been using.
I save white peel and stick labels like come with anything like VHS tapes and cut them up for labels because that's very much like the 3m tape.
I believe "normal" is to have the outputs on the top and inputs on the bottom but I always preffered the opposite - like a Coke machine - you put your money in the top and the stuff comes out the bottom. Heck I'm like that.