OK, thanks for the tips... but are tasks set by simply looking at the
weather predictions and picking a few reachable waypoints, or do
people get creative / devious with it?

Back in auto-racing, we'd try to design courses that challenged people
and made them think, or make tough choices (like providing a slalom
section that required the driver to sacrifice speed if they took a
certain line, or require them to think ahead and exit the previous
corner in a non-standard way in order to set up for the optimal slalom
route, etc).

I would think you could do the same thing when setting soaring tasks.
For example, picking a pair of turnpoints that require the pilot to
make a choice between flying along a ridge at an angle to the course-
line (and then "jumping over" to the turnpoint), or sticking to the
course-line and using thermal lift only. Or setting turnpoints at
opposite ends of a big lake - requiring the pilots to make a judgement
about the winds and airmasses to figure out the best side of the lake
to fly along. Or if the competition area has a plateau or expanse of
land at a higher altitude, place a turnpoint not far from the ridge or
hill that forms an "edge" of this raised terrain and make sure the
course-line has the pilots trying to decide wether to soar over the
raised terrain, the lower terrain, or the series of hills/ridges that
separate them.

Obviously you don't want to make the tasks too hard, but aren't tough
decisions part of the fun (& the challenge) of soaring?

Learning how and when to place these "traps" or decision-points within
a larger task has got to require some careful judgement and experience
on the part of the task-setter(s). So how does one go about acquiring
that judgement and skill?

--Noel