I noticed you're in CA. Have you been to Intelligentsia Coffee? You should check it out if you haven't. They are the Stumptown of the midwest.
As to correctly grinding, Stumptown explains it better than I can, "It is important that the coffee be ground medium-course with a quality burr (rather than blade) grinder. By grinding the coffee this way, you are allowing for a more even extraction resulting in a fuller bodied and more nuanced cup. Blade grinders chop the coffee rather than grinding it, resulting in uneven and unpredictable particle size. This results in uneven extraction, leading to coffee with increased bitterness which is less true to the flavor profile of the coffee. In addition, the lack of uniformity in particle size results in inconsistent results from cup to cup." -from the Stumptown Chemex Brewing Guide
Whenever I train new baristas I always suggest they think about how water flows through sand. You want the water to flow through the coffee as evenly as possible because you are extracting the oils on the grounds.
Freshly grinding is also important, because those oils you are trying to extract will begin to dissipate as soon as they come into contact with heat, oxygen and light. If you are using pre-ground coffee there is very little flavor left to extract.
Improving grind quality can be as simple as a hand grinder (Hario makes a pretty cool one, the Skerton) or there is also the more expensive Baratza brand grinders, which I use at home.
All grinders are not the same in terms of setting and grind size, so finding the spot on your grinder can take a minute. This is a helpful tool to find your Chemex setting and drip setting. http://www.ineedcoffee.com/03/coffeegrind/
If you are still finding bitterness in your cup, tap water, the coffee itself, and water to coffee ratio could be the culprit.