a) get a good piano
b) get at least two condensers. i just mic'd a piano with a Rode NT5. I only had one mic at the time, but the piano sounded really good through it. NT5s come in a pair and definitely worth the price for two small condensers. If micing a grand piano, i recommend putting one near the higher strings about a foot away from the hammers (the opposite way of the keys). And then another around the same place but on the lower strings.....maybe even further away from the hammers to allow the lower waves to have time to resonate.