My dad is a Certified Starbucks Coffee Master (yes, it's a real thing - he had to take a test for it and everything!)... so I've listened to him tell me all about how to make good coffee. *rolling eyes*
Get a GOOD grinder - a burr grinder, NOT a blade grinder - a good burr grinder can be had for $60, but they can run much more $$ than that.
Grind only as much as you are going to use RIGHT AWAY. Going to make 4 cups of coffee? Only grind as many beans as you need to make 4 cups. As ground coffee is exposed to air, it becomes more bitter and less flavorful. ETA - it should go without saying that you should avoid buying already ground coffee for this reason!
"Good beans" are kind of "in the mouth of the beholder", since everyone has such different tastes in coffee. Try a few different types of beans (from different geographical locations) so you can really get a feel for different types of coffees.
Your coffeemaker is very important. The BEST method for making good coffee is french press. Hands down. Make sure, if you use a french press, to grind the coffee accordingly - it should be a coarser grind than for a drip coffeemaker.
There's a lot of science behind coffeemaking... and I am not a Certified Coffee Master like my dad is, so I can't really explain it all. But these are the things he's drilled into my head over and over.

Hope it helps!