There are dozens of methods to make a decent coffee, but I'm going to concentrate on one method: drip coffee. This is the process used by American coffee machines.
Buy a decent pot. While there are numerous features to consider, make sure the machine is powerful enough to brew with boiling water. A decent pot will be at least $40, but the quality of your brew will be well worth it. If you don't want to splurge on a good coffee maker, a single-cup coffee filter will work fine. You can pick one of these up at your grocery store for about $5.
Whole beans are able to retain their own flavor while picking up less flavor from things around them than ground coffees. Grind your beans at least once a week; grinding before each pot would be even better. Coffee beans run through a burr grinder will have a better consistency, but most of them get gummed up by the oils that coat flavored coffees. If you drink these, buy a simple blade model.
Getting the right flavor is a matter of extracting the right amount of compounds from the beans. Most manufacturers will recommend one teaspoon per cup, but your mileage may vary. If your coffee tastes bitter, you're extracting too much and need to use more coffee. If it tastes flat, you're extracting too little and need to use less coffee.
Drink the coffee as soon as it's made, or turn off the machine and drink it cold. The hot plate underneath the pot will continue cooking the coffee until it ruins the flavor.
Cream and sugar should be added to the cup after pouring the coffee. Non-dairy creamer is made only to be cheap, not good. Also, it's unusually flammable.
If you are lactose intolerant, use soy milk instead. If you want the flavors that creamer comes in, use flavoring syrup.
Posted 3484 day ago