Video transcript
A run of four in five cells has only two placements. Push it left and then right: the three middle squares occur in both placements and are guaranteed, while the two edge squares remain unknown.
On the Teacup puzzle, the second and third rows each have a clue of five, so every square in those rows is forced. In the first column, the clue of four can extend from the top edge through the fourth row. The bottom edge must therefore be empty.
The last column needs two squares and already has its two middle squares filled. That run is complete, so the top, fourth, and bottom edge cells are empty. Empty marks are deductions too: they shrink the space where other runs can fit.
The top row needs four connected squares, and its last edge cell is empty. The four remaining cells fill the row exactly. The fourth row works the same way. Finally, the bottom clue of two completes the picture.
Scan edges, completed runs, and clues almost as long as their lines. They often remove the most possibilities first. Replay the exact Teacup puzzle and look for those anchors.