GM Prep Tip: Wiggle Room
I'm not trying to insinuate that newer GMs want to railroad players, but more often than not they expect the PCs to behave in a certain way. Truth be told, I don't think this expectation really goes away with more experience.
The core issue is that as a GM we are working from a different knowledge base than the players are. We get to know more about the bigger picture and less than the PC's motives.....and even less about the player's motives.
The key to preparing for this as a GM is to integrate a little bit of flexibility to your adventures. Do you really need to have everything mapped out into fine detail? If the players take the Northwest trail out of town instead of the Northeast trail can they still manage to find the monster's lair? Sometimes you do really need to have things set in stone, but other times you can be really flexible and others you can give yourself just a set amount of wiggle room.
You have the adventure all planned out, left the clues for the players to find, but still they go along the "wrong" path. Instead of that cave being NE of town can you shift it to the NW? If the players go SW then maybe you can decide that is too much of a deviation.
Flexibility is even more important when it comes to timing your adventures. You don't want to be completely flexible to the point where it is like a video game where the monsters don't spawn until the PCs draw aggro, but most adventures don't need a strict timeline either.
I once heard a tale of a fan questioning a SciFi author as to the possible top speed of an often-used craft. The author responded that they didn't have a set speed, but instead their top speed was "The speed of the plot." When planning your adventures determine in advance your "wiggle room" and let the party succeed or fail based on their ability to perform within that range. What is the speed of your plot?