Ahh... coffee... The perfect cup. I bought a book years ago with that title. I figure that non-coffee drinkers will miss out on something about heaven... I bet God has some AWESOME coffee. We coffee drinkers will be sitting around immensely enjoying the awesome brews, and the non-coffee drinkers will just be missing out.
I used to drink primarily American coffee. I now mostly drink espresso drinks. When I was doing American coffee I started roasting beans in a hot air popcorn popper. I could duplicate the taste of any good medium (or light) roast that I could buy (but make it cheaper). What I found were the important factors:
(1) beans
(2) freshness
(3) don't add bad flavors
Everything else is WAY secondary (grind, etc). You have to have a quality bean that you like. My go to was Guatemalan Antigua. I also like some Indonesian beans like Sumatra and Java. Kona I like, but not the price. I don't care for any African I've tried. Your preference is subjective. Freshness (after roasting) is important. Green beans keep a long time. But the taste of any roasted/baked item doesn't last forever. The good flavor goes away, and the oils get rancid. Interesting thing is that coffee isn't at its best immediately after roasting. I don't know what it is. I've read about "out-gassing". Whatever it is, it needs to settle a little. For me, I'd roast what I needed for about a week. Didn't need to roast the same day or couple days. You can tell just by smelling the container of beans when you open it. The amora is there, or not (or bad). Grinding before a brew is the best, but I don't. I grind for a few days. I don't notice a difference. Again, the BIG factors are the 3 I listed (in my experience).
For (3), it can be anything. If your water tastes bad it affects the taste. I'm not a fanatic on this; I usually use tap water. But my tap water varies with time, and if I can taste chlorine, I'll use bottled water. Taste your water. If it tastes bad, use something else. I don't understand people using brown coffee filters. Just run water through one and taste it. Yuck. If your pot/cup is dirty enough, you'll taste it. Whatever method you use to make coffee, try it WITHOUT the coffee and taste the outcome. If your water/filter/hygene adds bad taste, you'll notice. Don't add bad flavors to a wonderful drink.
Several years ago I started drinking primarly espresso drinks, and I couldn't figure out how to roast, blend, whatever it takes to equal what I could buy. So I now buy Starbucks beans (Espresso, Italian, French roast. I like them all). I still grind for a few days. I always check the date on the bag. The date on the bag is 6 months after roasting and it makes a noticable difference. It is NOT the same after 6 months. I don't buy it unless the date indicates that it is fresh. I use a simple steam machine or moka pot. I had a pump machine for a while, but for my tastes, the 3 items in my list trump everything else. Fresh beans that I like with no added off flavors make a drink that I enjoy.
A few years ago I was in Rochester, NY and stumbled upon Canaltown coffee roasters. The best espresso drinks I've had. They roast their coffee and I talked to the owner/roaster. Unfortunatley it's not local to me and I'm not willing to pay the shipping costs to buy the beans. I did get a hint from talking to the owner that maybe I was over-roasting in trying for espresso. He indicated that the Guatemalan and Indonesian beans I liked should work well (I had wondered if I needed to add some robusta). I've not tried roasting again recently.
...add. When I make drip (American), I just pour a single cup using a Melita thing over a mug. I'm the only one in the house that drinks coffee. If I have a party (not often), I'll pull out a drip coffee maker, or just call out "anyone want espresso/cappucino?" and my steam machine will do 4 shots at a time.