Whether you’re playing a time test level or a level which requires you to make so many matches in so few moves, you have to remember that every move counts. Incorrectly moving blocks into places where they don’t match can really cost you, so be very, very careful, especially once you reach the third “world” in the game.
You can always replay levels you’ve already completed, or experiment during the easier ones and in tutorials, so you can always use this as practice grounds for when things get really tricky.
Aside from getting an easy 11-combo by arranging five identical blocks vertically and five more identical blocks horizontally with a space in the middle for the eleventh identical block, there are other ways to “make combos” in the levels that ask you to do so. This includes rapidly completing separate combos of six, five, or four, meaning completing a new match immediately after the last one. This would require you to have all but one block for the matches in place before completing them, so be sure to be on your toes and ready to move should you employ this strategy.
This will be especially handy when you’re trying to knock off impressive combo hits of ten blocks or more. The moment a new board goes up, single out the color that has the most matches, and work on that for the duration of the level. For example, you’ll want to keep making matches (as long as you’re within your move limit, if applicable) for blue blocks if you’re trying to set up a big blue combo.
If you complete a match of seven to ten blocks, you’ll get an eraser, while matches of 11 blocks or more get you a block with a “+1” on it, which counts towards the blocks included in the match. Use these blocks only when you need them, because once you use them, they won’t be reappearing in the level.