Experienced writers, how do you turn a nebulous premise into an excellent, solid story?

I've got a loose skeleton for the plot, but I'm not sure how to flesh it out. Do I just continually up the stakes and throw lots of (relevant) trouble into the way of the main characters? Everyone says that this is the way to do it, but won't that just create lots of boring problems? And if you're NOT meant to do that, what else are you meant to do to make it last the entire novel (and be interesting)?