A good cup of coffee is made up of about 98.75% water so it makes sense that the better the water, the better the cup of coffee. There are a couple of things you can do immediately depending upon what you have in your kitchen today.
First, if you have a water dispenser in the door of your refrigerator make sure you replace the filter and do so when your refrigerator tells you to. If you don't have a water dispenser in your refrigerator, buy yourself an inexpensive filter for your kitchen sink tap. For recommendations, take a look on House Cup Coffee's recommended equipment list.
Finally, make sure you keep your coffee brewer clean. Descaling on a regular basis (most brewers today notify you when you should do so) is important as it not only keeps the water clean but also keeps the flow of water optimal for a good pot of coffee.
Hope this first step to a better cup of coffee helps you enhance your enjoyment of this wonderful drink. If you have any questions, use the "Chat With Us" button on the bottom right side of the page. Cheers!