I've made a lot of mistakes working on the brakes of vehicles. Here are some tips based on mistakes I've made:
-It's okay to remove the glaze from brake pads and brake shoes with sandpaper. You don't need to be real aggressive. With brake pads, simply rubbing them on a concrete floor is often enough. As long as the floor isn't polished or epoxy-coated.
-Buy brake fluid in small bottles. Never save a partially-used bottle of brake fluid. Brake fluid will pull moisture out of the air, even from a bottle with the cap screwed on. Small amounts of moisture in brake fluid, when heated by braking action, can boil and make brake pedals feel spongy.
-Spongy brake pedals can also be caused by air in the system. Brake systems can have air leaks that don't actually leak fluid. Flared fittings that have small cracks, depending where they are in the system, can suck air without leaking fluid.
-Yes, you can work on brakes with screwdrivers, Vise-Grips and needlenose pliers. But you'll bleed a lot less if you spend the money for brake tools such as spring compressors and brake pliers.
-Anybody who says they "enjoy" working on brakes is exaggerating.