Here's a tip that might help you on the more challenging levels:
Whenever you begin a new stage take all the dots and stack them on top of each other in the middle. The dots will layer on top of each other. Now, one at a time, pull the dots off the middle stack. Don't worry about the dot's line that connects to the middle stack. That line will almost always be white until towards the end. Just make sure that the lines connecting to the other dots already pulled off of the stack are gray.
This will help with some wear and tear on your brain. It is easier when you're focusing on fixing one dot at a time and not the whole picture at once. Just try to break it down.