Five common mistakes
None of them loses the game. All of them cost minutes.
1. Digging into the centre
The centre stays locked longest. Starting there means hitting a wall ten moves later.
2. Forgetting the layers
A tile can look free and still rest on another one. Always check what is underneath.
3. Ignoring the edges
Edge tiles are almost always playable. Skipping them throws away free moves.
4. Being afraid of the hint
A hint costs ten seconds; five minutes of searching costs more.
5. Refusing to shuffle
Sometimes the board really is locked. Shuffling is part of the game, not a surrender.