The best indication you have received intuitive information directly from your higher self is it will come in as a certain and neutral knowing. It's something you understand at your core without going through any reasoning or emotional process. When a direct knowing from your higher self hits you, you will feel calm, open, and receptive. A part of you will recognize your soul's wisdom and will not contract away from the information.
An intuitive direct knowing can be information that will happen in the future or valuable insight on a past or present moment. The exact reason for the direct knowledge is often unknown as your higher self works on a need-to-know basis. Yet somehow, you'll understand this clear knowing as something significant. Furthermore, as a more general definition, direct knowing is any piece of information that expands your awareness that you are a spiritual being having a human experience.
Direct knowledge can be likened to an "Aha!" or "Eureka!" experience, but it's not necessarily the same thing. It's similar in that you understand something clearly that you haven't before. However, the information received doesn't filter through other layers of your consciousness or your five physical senses before arriving in your conscious awareness. The knowing will not have the emotional charge of a desire or the mental overlay of an assumption or judgment. Key hallmarks of a direct knowing are that it's unexpected, unequivocal by nature, and will always prove valuable and accurate over time if not immediately.
You most likely already had experiences with direct knowledge in your life, as your higher self is always talking to you. Ask yourself if you have ever known something without any proof or reason. For example, you just met a new person, and you instantly receive a direct knowing that you will have a significant relationship with them. If your intuitive hit about this new person is indeed a direct knowing, this piece of information will prove to be true over time without coercion or manipulation. Your relationship will have value and progress organically.
Remember that the gold standard of hearing high levels of intuitive guidance is to look for direct knowing information. If you get it, apply it, and you will likely realize you just hit gold.
For more on direct knowing, [Read: How the Higher Self will Take You Higher]