tighten up

verb5

1. •
   To make sufficiently tight.
2. •
   To fix something or make it correct.

   • As noted in the last chapter, you should tighten up your argument and prose when you revise the first draft for substantive change. — 2012
3. •
   To become, or make, more stringent and ungenerous.

   • The church was tighening up on matters sexual. Until the middle of the tenth century it had been quite routine for priests to be married. — 1999
4. •
   To become tense and restrained.

   • You must follow every change because every change affects your play. If another player loses a big pot, you must ask yourself how this will affect his play. Will he go on tilt? Will he tighten up? — 2006
5. •
   To become focused and serious; to stop any vacillation or inconsistency.

   • Plainly winter was at hand. "Just as well we started when we did," said Bill. "No tellin' when she'll tighten up." "May do it any time," Sam agreed. — 1922