Proper cleaning and sanitation are vital to making great beer at home. Before beginning your brew day - always ensure that you have thoroughly cleaned all of the equipment with a non-scented cleaner.
For any equipment that will contact the wort once the boil is over, you will want to ensure that it has also been sanitised. This typically includes your fermenter, and any hoses that come in contact with the wort, as well as an immersion or counterflow chiller (if applicable), and any bottles or kegs that you plan to package the finished beer in.
If using any plastic equipment, always check for micro-abrasions on the surface of the plastic. These areas can be difficult to thoroughly clean, which can lead to the development of harmful bacteria in your beer.