I'll take a guess as an ex-glider type, though I have never been even near a competition, some of the folk in my club used to yack this stuff and I have been along for the ride during one prep for competition.
What you learn by flying an area (it is all soaring, and glider
is a no-no word among sailplane pilots), is what to expect from the wind, the sun and the relationship to the terrain below.
Features .... such as parking lots, a factory complex or a quarry can, dependent on the angle of the sun generate lift ... your eyes constantly search for such "generators", such as a freshly plowed field.
As these features heat, the air above them will begin to rise and then "overcome" the "tension" of the surronding air mass and sometimes they "pop" suddenly like an air bubble in a pot of water .... the primary target you look for is a wisp of a developing cloud or trace of vapor.
What you do in essence in cross country soaring or in racing is to gain altitude and when you max it out, head off at full speed towards the next point ..... circle, circle and circle the "generator" in order to buy some more altitude and then race off towards the next point. The base of that little white cloud is pretty much as high as you will go.
Mountains and ridges can and will generate lift depending on the wind always keeping on the windward side of the ridge. The leeward side can kill you ... don't ask how I found this out.
The racing our club did was a "drop" at X altitude over the field and then a scramble from point A .... to .... B ..... to ....C ... and then home.
There are some technical errors in the above but I have tried to keep it simple.
I something like "The World Cup" I'm sure there are event categories for distance and altitude ..... that when not done in a "Super Q" .... are pretty safe.