How to store coffee?
One should always store coffee beans in a glass, air-tight container. Air and moisture are coffee's principle enemies. Glass is best because it doesn't retain the odors of the beans or the oils, which could contaminate future beans stored in the same container. A mason jar with a good lid works well. If you use glass, make sure the container is not exposed to light, as sunlight can also reduce freshness.


Do not freeze coffee for regular storage. There are two key problems here. One, the freezing will damage some of subtle tastes in the coffee and two, when the coffee is taken out the container will sweat, exposing your coffee to moisture.
If there is not a roaster convenient to you, you should consider taking up home roasting as a hobby. It's not at all difficult and can save you a few dollars while improving the coffee you drink. When you are replacing your coffee every few days with coffee fresh out of the roaster then storage becomes less of an issue.
Is water important?
It is quite simple: Coffee is at least 98% water. The higher the quality of water, the higher the quality of the resulting cup of coffee. If your tap water tastes good at room temperature tap water is probably fine for making coffee. If your tap water has off flavors then your coffee will have off flavors. Many people use filtered or bottled water for their coffee. There is a difference. Some of the newer more expensive coffee pots come with replaceable charcoal filters built into the machine. If at all possible don't use distilled water. It is missing minerals that makes water pleasing to drink. Please note that your taste buds are more acute when tasting warm liquids so it is important to taste your prospective water at room temperature since you will be drinking your coffee warm. The quality of a brew depends on the following factors (in no particular order):


Fact: If you are buying one of the world's  Hawaiian coffee provides by USA Coffee Company, bean quality is only the beginning of a great cup of coffee. The best bean will taste bad if any one of these other characteristics is out of place. Not all beans are equal.

Fact: A coffee can in the supermarket often contains large amounts of robusta, low quality Arabica beans and past crop (old) beans.

Fact: Once you have freshly roasted and ground coffee, good water and equipment free of oil residues from the last brew, quality of beans makes a huge difference.
Just how much ground coffee do I need for x amount of coffee?

 
a. Whatever seems right to you.
b. It may change slightly from coffee to coffee and according to freshness and varietal.
c. What the Specialty Coffee Association of America (SCAA) has to say:
A cup is defined as 6 ounces of water before brewing. This will produce 5.33 ounces of brewed coffee. Or 125 ml & 110 ml for Euro style coffee makers
The SCAA defines 10 grams or .36 oz per cup as the proper measure for brewed coffee if using the American standards. If using Euro standards the measure is 7 grams per 125 ml.
To further confuse things I will add a few more measures:
3.75 oz per 1/2 gallon
55 grams per liter
2.25 gallons per 1 lb.
If you want to know more check the SCAA's web page at www.scaa.org.
d. The easy answer for most home coffee brewing is 2 Tbs. per 6 oz of water. A standard coffee measure should be 2 Tbs (1/8 cup) . Be warned some coffee measures deviate from the 2 Tbs. standard. Some are even as small as 1 TB.