This is something I really don't want design space used on as far as rules and such as part of the main/base game. Straight skill challenges, if not properly used within the flow of the game, are awful. If you just kind of float in to and out of them, they work well. Some times though, it's isn't an actual "skill challenge" but rather a use of basic skills. On a number of things I generally let a player RP through it and only use rolls where necessary, as in outside the box or norm activities. A basic guide of economic structure would be cool though.
Example: You RP through finding a source of stone for your fortress but then you want to haggle on the price. There a Diplomacy roll might be needed if the margin is over 5% or whatever you decide.
I find often that a number of DMs aren't bad, they just lack comfort or confidence in their "grasp" of the rule structure. My answer to that is don't worry about the rule structure past what you need to. Never let the rules get in the way of your fun, only let them enhance it.