In Burning Wheel (Gold, also Revised), there are some stats — specifically, Perception, Faith, and Resources — that only advance when you succeed at a test.
This makes advancement much more difficult, since you need to actually pass Difficult and Challenging tests — by definition, tests that you're likely to fail, and tests that you have no hope of succeeding without extra effort, respectively; whereas with other skills you merely need to attempt them (well, attempt them and survive the consequences of failure).
However, this is Burning Wheel, so artha is limited and tests don't happen without something at stake. The game's ethos is that you should put something on the line and face danger head-on, but also put some thought and strategy into your approach in order to actually persevere. Doubly so for the "only successful tests count" stats because there's no consolation prize for failure.
For instance, I've been able to advance Perception at the same rate as Will and Power while actively trying to advance and shade-shift Perception while largely ignoring those other stats (and rolling them significantly less often than Perception). Meanwhile, advancing Resources seems like a delicate balancing act because failing tough tests leads to tax, which can actually permanently drain your Resources if you're not careful.
So, what's the best way to pick up the successful Difficult and Challenging tests needed to advance Perception, Resources, or Faith in real play, where artha is scarce and failed tests have real consequences?
(If it involves using a limited resource judicially, tell us how. If it involves setting up certain specific fictional situations, provide some guidance on how to do it awesomely. Et cetera.)