As discussed in a basic fashion in video #4 in the intermediate series (https://www.youtube.com/watch?v=RRm-FGm779I&index=5&list=PLXl66WQfmAd3sO9MnR0x7hv5A85CogA-l), knowing how many mines are left and counting where they could be is a tactic that can actually help you win when you would otherwise have to guess. This video explains how that works in more detail and walks through a number of examples--and then leaves five examples for you to try to solve on your own! You can view them starting at 13:51 in the video, or see them all together in this imgur album: https://imgur.com/a/7VbsNST
Previous strategy video series:
Beginning strategy - https://www.youtube.com/watch?v=6_HmB4HJDf4&list=PLXl66WQfmAd1Amu_58icJjwSeTBUxSt8-
Intermediate strategy - https://www.youtube.com/watch?v=GSUo5dmk-Os&list=PLXl66WQfmAd3sO9MnR0x7hv5A85CogA-l
