You answered one of the best ways in your second question.
2. Yes. Try that!
3. I reboot my phone or find it's icon and start it again.
4. Besides what you noted, BE BRUTAL ABOUT INSTALLED APPS. Remove any you can, disable all you don't use.
I have a Motorola Moto E with Android kitkat 4.4.4
I looked at Developer Options>Process Stats and it said "Device memory is currently critical"
What can I do to fix it?
Can I Force Stop apps I'm not currently using?
How do I enable an app I have Force Stopped?
Does anyone have a solution?