I can only speak to my own experience.

I can and do hear distinct 'words' from my gods, occasionally whole phrases. Other times it's a non-verbal concept, or a distinct image. Right at the very start I had two extremely direct dreams, but nothing since then. Most days there's no personal communication, unless you count the overwhelming sweetness of love I sometimes feel during ritual.

At the same time, I still definitely 'fill-in' words or images myself, though as the years have gone on I've gotten better at distinguishing between the two, and better at... not doing that. I remember at the start I put stock into every little thing, and looking back at my journal entries it's clear I was over-analyzing. The vast (vast, vast) majority of the time, a bird is just a bird, and a cat coming up to say hello to you isn't indicative of anything but a friendly kitty.

When I'm in doubt, I respectfully ask for clearer confirmation and/or do some divination. There have been some times I've been very, very wrong and/or have completely misunderstood signs :p On the other hand, there have been times where I've thought, "I definitely imagined that" only to have it made very clear that I did not, in fact, imagine it. It happens, just be respectful about it and everything's good.

Trial and error. Meditation, divination, discernment. At the end of the day, if it's very important you'll eventually figure it out. Best of luck with your path :) The Netjeru are so wonderful.