Probability reasoning
Level: Advanced
When logic runs out, pick the safest cell.
On Advanced and Expert boards, you'll rarely reach a position that no logic can confirm. When that happens, estimate the probability that each cell is a mine and choose the safest one.
For each candidate cell along the border, count the possible mine arrangements and compare the probabilities. Cells 'toward the wide clearing,' where less information is open, tend to be safer on the whole.
Probability is strictly a last resort. Getting into the habit of double-checking with subset deduction and total counting — to be sure no confirmed cell truly remains — before you guess will raise your win rate.