You cannot directly percieve your failure to adequately perceive something. This failure must be inferred. Consider a hypothetical example:
Suppose a man with a rifle visits a land of savages. The savages are amazed by the stick that shoots. They get a piece of wood, carve it to look like the rifle, and paint appropriate parts appropriate colors. They hold it up like the visiting man did, say the same words, and make the same motions - but nothing happens. They try different variations, but they just can't get it right. They eventually conclude that they're just jinxed, and they somehow can't get the thunder-stick ritual right. Of course, the problem is not that they have gotten any of the gestures or incantations wrong - the problem is that pieces of carved wood do not shoot bullets! The task is not nearly so finicky as they think it is, but it is fundamentally different.
This example isn't actually all that hypothetical - this is the very phenomenon which causes cargo cults.
So how can you tell? Suppose you're the savage, or the South Seas islander. How do you ascertain that there are fundmanetal phenomena you're missing, given that by definition you know nothing about these phenomena? Clearly the presence of phenomena which are not understood must somehow be inferred, as the whole problem is that one does not know how to directly perceive them.
The answer is that the correct representation is robust. It's the opposite of magic. In magic, you don't understand the causal connections between what you do and what happens. Instead, you must perform memorized rituals in a precise fashion. If something looks like magic to you, you don't understand it yet - you're observing the form of the phenomenon, and missing the important parts.
Be particularly suspicious if you have never succeeded at something. If you sometimes succeeded and sometimes failed, your unconscious would have a reasonable chance of figuring out what was different between the two sets of experiences. However, if you have never succeeded, it is easy to have some very mistaken beliefs about what is required to succeed, and pursue avenues of endeavor which will actually have no effect on your ability to achive the desired result. When what you're doing isn't working, don't keep doing the same thing with more and more energy - find something else to do instead.
A very similar manifestation is a feeling of being unlucky or jinxed. If other people are getting results which you're not, it isn't because God has smiled upon them - it's because they are perceiving more useful aspects of the situation than you are and responding to things that you haven't yet learned to distinguish from noise.
One of the most common times for this phenomenon to manifest itself is in interpersonal relationships. For example, suppose you get rejected. If you find yourself wondering whether would have been successful if you'd changed some small part of your presentation (such as dressing up more, or going to a different restaurant), you're missing the point, and you're not looking at the situation with a useful framework of concepts. If you've got a reasonable set of abstractions, it should be immedately obvious why you got the results you did.
Now, suppose that instead of lacking the concepts to understand a situation, you have some concepts which are applicable to your situation, but aren't the best. Suppose you can identify some sort of behavior (such as "dancing well"), and yet this does not allow you to reproduce the behavior yourself.
This situation implies that the building blocks on which you have based your understanding of the behavior are not the correct ones for the production of the behavior. To continue the previous example, if you want to dance well, you need to understand what "good dancing" is in terms of what it feels like to engage in it. If, on the other hand, you understand "good dancing" in terms of what it looks like, you'll be able to identify it in other people, but you will not be able to reproduce it yourself - at least, not until you spend a number of hours in front of the mirror learning how it feels when you do things which look good.
You'll often perceive this as some sort of gap or chasm you can't cross. You have a representation for where you are, and you also have a representation for where you want to be, but you can't link the two of them and figure out how to get from the former to the latter. Although you have a representation for both the present and desired states, at least one of these representations isn't very good, and should be translated into some other concepts instead.
Finally, it is sometimes the case that instead of lacking anything, you have superfluous and counterproductive concepts which are making things difficult.
Suppose you start by thinking about what to get your spouse for your anniversary and instead end up feeling angry and resentful about something that happened on the last vacation you took together. You weren't trying to dwell on that, but ended up derailed by some concepts which were linked in a way that didn't take you where you wanted to go.
This problem tends to manifest itself as a feeling of being stuck. You start with a question or desire, and then end up somewhere that isn't an answer or a plan, but is a place from which you cannot get any further. Often this will happen repeatedly - every time you try to consider a certain problem or investigate a certaind class of phenomena, you'll end up in the same place, which isn't a useful place and isn't somewhere from which you can progress further.
In order to make progress, you'll need to start making your some of your thought processes conscious to give yourself more choices; you can then choose to go in a different direction than the one which leads you back into your useless rut.
To summarize: