Once your geared, defiantly a blacksmith. I use to to walk around asking people for there unwanted drops though I found its much more profitable to find one person to loot for since you don't have to waste time asking and then wait for a response. To save time with the previous way and the sanity of those your asking, ask if you can loot them whenever you see them. Then memorize there name. They will either say yes, only once or no. The hardest part about this is usually people are so covered with items that you can't see there name. If your poorly geared you would want to loot for a priest since they can help keep you alive and they can kill faster.
The hardest party about looting for one person is find someone to loot for(I know it sounds crazy). Most people will say no because they think for some strange reason they can spend less time killing enemies, more time picking up items and be more profitable because profits are not split.
I personally have earned my first MVP cards using this medthod though a major downside to this is when you can't find anyone to loot from hardly and no one wants someone to pick up items then you can't make money that well in niff.