There is an app called flow that I play with my son. We race to see who can get the puzzles finished first.
The game has a grid with different colored dots that come in pairs. The aim of the game is to connect all the dots of the same color.
When I first played the game, it took a while because one color line would block the way of another colored line.
Like any game, I tried to figure out rules and patterns that would help. The pattern or “heuristic” that I came up with is that if you could join two dots by keeping the line on the outside edge that would be the valid connection. This heuristic works 99% of the time. Now the game is simply finding two dots that you can connect by staying on the outside edge. Once those are joined, that line is the part of the outside edge. You then look for the next two dots you can join. Most puzzles can be solved following this simple heuristic.
The heuristic also points out a pattern in problem-solving. You don’t need to solve the whole problem; you just need to solve part of it and then look at the result as a new problem. Keep doing this and eventually, the whole problem is solved.