I sometimes use a Q-Tip or take a thin cloth meant for cleaning lenses and wrap a corner around a toothpick. I used to have a tempered glass camera protector, but I took it off a few days later. 1) It kept coming off and 2) I found it practically protruded past the camera cutout on most of my cases. For what it's worth, the protector came with a tiny alcohol wipe and it didn't damage the camera when I used it.
I use a bulb blower, they are made for cameras and lenses. Does a really good job of cleaning the dust from the recesses around the lens. You can find them on eBay cheap.