One of the things you have to contend with is background noise. There are so many thoughts and ideas in your head being fed by memories, sights, sounds, smells and feelings. They alone can be overwhelming, add to this cacophony is hearing His voice which seems to be the quietest.
They call it that still small voice. The reason it is so quiet is that all the others speak to your mind directly whereas He speaks to your spirit. There is no competition or at leat very little. The question is how can you differentiate between your thioughts, His thoughts and perhaps the devils attempts to influence you.
If I can suggest one simple answer ‘peace’. If what you hear sends you into a tailspin, confusion, doubt, worry, despair etc then you have a right to challenge what you have heard. This can also happen when He has spoken to you and you add your bits to it, extrapolate His words, adapt it, multiply it etc you get the picture.
It is never that our brains/minds are the enemy, far from it, rather it is perfect when our minds align with our spirits and particularly when our spirit listens to The Holy Spirit. It is a process of learning and I am still learning. A hard lesson especially when the pressure for a solution to a problem is on.
Train yourself to listen. It is a process and an art. It is a discipline but well worth it. making mistakes is all part of the learning process.