Cooling your wort!
Its key to cool your wort as fast as possible once its finished boiling in order to pitch the yeast, and get fermentation started right away. This helps avoid potential bacterial infections. The quicker we can chill the wort, the better! Even though chill haze can be drastically reduced by the addition of hydrated Irish moss in the final 15 minutes of the boil, quick cooling of the wort can also permanently precipitate cold-break proteins out of the solution. Slow cooling will have the opposite effect, increasing haze, and creating an environment more prone to bacterial infection.
* How to cool wort with cold water *
Most extract home brewers end up with about 2 gallons of hot wort at the end of the boil. Super cold water is a home brewers friend in these situations. Ready for some math? If you pour 2 gallons of boiling wort into 3 gallons of 70 degree tap water, you'll be waiting several hours for the wort to cool below 80 degrees, even with your fermenter sitting in a tub full of ice water. Instead, sanitize 3 empty juice/milk jugs, fill these with cold water and place in the freezer for a couple of hours before your boil is scheduled to finish. Before you siphon the wort off into your fermenter, pour this freezing cold water into your fermenter, then add the hot wort, this will drastically reduce your wait time to get the temperature down to pitching temps, ideally under 80 degrees farenheit.
Never use commercial ice to chill your beer as it often contains bacteria that could spoil your beer, this includes household freezers, which also may contain bacteria that could end up in your ice.
If instead, you boil full 5 gallon batches (good for you), you wont have the benefit of adding cold water to cool your wort. For this amount of wort, you will require the aid of a heat exchanger. There are several varieties of wort chillers available to chill your soon to be home brew.