Here's what I think the answer is: You say "try verb + ing" when you think doing the verb will solve the issue that you're talking about, or help to understand the problem. some examples "I'm having trouble with this" "Try thinking about it", "My hand hurts" "Try moving it". Another way of thinking about it is that you're focusing on doing the action, you aren't seeing if they can move their hand, just if moving it will help stop the pain. You say "try to" when you want to see if they can do the action, for example if someone is ill and hasn't eaten anything you would say "try to eat this", I might say to you "try to think of your own examples". Another way to think of it is that you're focusing on completing the actions. You want the ill person to eat something in the hopes that they feel better, not because you think that eating something will make them better. You thinking of your own examples will help you get better, but the focus isn't on the process of thinking of the examples. I guess as a conclusion, you say try to when the focus is on doing the action, and try verb + ing when the focus is on completing the action. One last example: "Try eating this" - says to me that eating will solve whatever we were talking about previously, after eating things will be better. "Try to eat this" - says to me that they want to see if I can eat it because it's difficult to eat (either it's hard, tastes bad, or I was having trouble eating things before, something like that). I really hope that helped, I'm not used to thinking about my native tongue so much!