In block puzzle games that hand you three pieces at a time, the most common way to lose is not a bad piece. It is a board that was already too full when the bad piece arrived.
Clear when you can, not when it is pretty. A single-line clear now keeps the board open. Waiting to set up a big combo works until the one piece that does not fit shows up.
Keep one large open area. Try to leave a 3x3 space somewhere on the board. It is the only spot where the biggest square and L-shaped pieces always fit.
Place the awkward piece first. When you get a long bar or a big square with two small pieces, put the big one down first while you still have room. The small ones fit almost anywhere.
Avoid single-cell holes. A lone empty cell surrounded by blocks can only be filled by the one-cell piece, which is rare. Every hole like that is a line you may never clear.
Look at all three pieces before moving. Plan where each will go so the first placement does not block the other two.
You can practise these habits for free in the browser at Block Blast, which also hosts other quick puzzle games such as 2048.
Disclosure: written by the blockblast.co team.