Using a yeast starter is one of the easiest ways to significantly improve the quality of your homebrew. This will activate your yeast and multiply the cell count in order to ward off bad flavors and bacteria that could take over your wort.
Stainless steel 2 micron diffusion stone is useful for aerating wort with room air and an aquarium pump. Barbed fitting, fits 1/4" I.D. tubing.