Mostly I taught myself - stumbling along over 6 to 12 months or so - gradually discovering its full richness. I tried I-Google. But I ended up back with the basic Google Reader, as its "less pretty" functionality suited me better - specifically the ability to tag (aka categorise or metadata) feeds.
There are a few how-to's around, including :
Take the trip to work out which Google Reader "how-to" suits you.