On our training rides, however, that's not the case. Our routes are almost always not marked with arrows or other route markings, so it's important to study and understand the route sheet before beginning your ride. And on the other side of the equation, it's important that you get a route sheet that's accurate.
Here's a 2004 article from the Randonneurs USA newsletter about making route sheets for long-distance rides. Some of the points are very applicable to the type of riding we do, others not so much. A couple of soundbites:
Superb cue-sheet writers (and I have known several!) all have their own idiosyncratic styles. Nonetheless, their cue sheets all have two qualities: accuracy and clarity. Cue sheet design is particularly critical for brevets, where routes are longer and include more turns than on the average club ride. Brevets should be challenging because of the terrain and the distances involved, not because of poor cues that cause riders to get lost.
... The cue sheet should point out significant road hazards – metal bridges, railroad tracks, poor road surfaces, unpaved roads, unchained dogs, gravel in turns, sharp switchbacks on steep descents, etc. Highlighting such notations in bold print helps to warn riders in advance. I also note ambiguous road signs, confusing turns, and unmarked turns. Additionally, it is very helpful to indicate T intersections, stop signs, traffic lights, etc., and I always make special note of a turn that takes place in the midst of a descent, indicating that it’s easy to miss (“ETM”).
There's no single "correct" way to do a route sheet, and you'll no doubt see many different styles during your ALC training and on other club rides and organized events. When I make route sheets for training rides, I make them look almost exactly like route sheets from the event in June so that you'll have experience in reading sheets that are done in that format, including rest stop markings and the all-important scale of the elevation chart.
Good route sheets usually are the product of hours of research, writing, and editing, so be sure to thank your ride leaders ... and, perhaps, even be somewhat understanding when slipups occur.