I have been hit or miss with development of an ability to sense the unseen.
It seems that prolonged sea times aboard my boat helps me tune in better. I can't explain why just getting away from land helps.
Two examples:
Exploring Tabon Caves on Palawan I stopped at one point and wouldn't go into one section of a cave. I announced no one go in there. Something bad occurred here.
At the time I was being followed by one of the staff from the National Museum. I return often to Tabon Caves. I am specifically searching for cave art and think I have found some. On about my sixth visit, I was asked why? Why did I react that way at that point in the cave? I said it is just something I felt and knew. I was informed that I am the second person to do exactly the same thing at that specific point.
Example two: Negros Island
I was kayaking along the coast when I suddenly pointed at the shore and said BAD! We do not go here! I was with someone from Negros and he asked me, "Why?". I sad something bad here. He informed me that somehow I managed to point to the exact spot the body of a tourist was found. The tourist had been raped and then thrown from the cliff and landed exactly where I pointed.
Once I was hunting along a hillside and had just given up when I got a message to look again. That story soon.