Sticking with the metaphors: if one thing's certain to increase your chance of tumbling into holes in the ground, it's walking forward with a telescope held up to your eyes.
You won't generally see many people doing this in real life, but it's a lot more common for PhD students. Metaphorically speaking, I mean*.
At the beginning of a taught degree, you're probably focussing on your first modules, the upcoming classes for those modules, perhaps the coursework or other assessments looming at their conclusion.
At the beginning of a PhD you won't normally have any of those things. As a result, it's all too easy to focus exclusively on the end result: a finished PhD thesis.
This isn't a bad thing in and of itself (a finished PhD thesis is what you're here to produce, after all). But that finished thesis is still a fairly distant target at this point. And if you're focussing on it too exclusively, you run the risk of missing more immediate obstacles and opportunities (remember the telescope).
This can easily lead to you become disorientated and disilusioned. Without a set of checkpoints and shorter term goals, what should be a pathway through your PhD can look a lot more like a wilderness in which you don't really feel like you're researching a PhD at all. If things get bad enough, you might not be.
*I suppose it's possible that Geography or Environmental Science researchers might walk slowly forward holding a telescope up to their eyes. But they probably have training for that.
The solution? - Replace telescope vision with map vision
A PhD actually lends itself very well to structure and short-term goals. You just have to identify them.
Start by chatting with your supervisor. Set a timescale (and direction) for your literature review and work out what the next steps will be from there. Experiments, drafts, training, related projects: have an idea of what you want to achieve and roughly when.
Short-term goals will keep you moving and give your PhD a welcome sense of rhythm and routine.
As you go, mix in a few medium-term goals (chapter drafts, conference papers, etc). These can function as more significant checkpoints, allowing you to mark and measure your progress towards that finished thesis.