One of the most common, on the Nav part of the Skill Test, is for a candidate to spend appreciable time calculating a true track, adding the effect of wind after herculean efforts with the whizz wheel and then applying both variation and deviation, arriving at a Compass Heading of something like 147.69 degrees, then getting airborne and steering anything around 30 degrees either side of it without bothering to regularly reset the DI with the compass.
Predictably, disorientation and getting lost inevitably follow.
Most light aircraft DIs are accurate to about plus or minus 5 degrees and if the heading is steered even accurately to plus or minus 10 degrees the waypoint will usually turn up on one or other side of the nose after the appropriate time has elapsed.
When you've worked it out as accurately as possible,
steer it as accurately as possible!! Works every time!
Level 400