Laying in the tank trying to control random thoughts is like herding cats. And there are days bringing the focus back to breathing just doesn't work.
There is one tool I come back to over and over again. Progressive relaxation.
It's a fancy name for simply drawing your own attention to each part of your body and imagining the muscles letting go or melting into their most relaxed state.
It gives me something to occupy my brain until the hazy theta waves finally take over, and my fidgeting makes way for some seriously good tank time.
My own sleep issues make audio guided imagery of progressive relaxation a close personal friend. But in the tank we don't have that luxury.
Fortunately it's a simple enough exercise we can simply make up as we go along. But if you're looking for some guidance, listen to the progressive relaxation below a few times. Or do a search and you're bound to find many online. You'll get the gist in no time.
Let me know how it works for you!