If I'm going to finish my homework by Thursday, I had better get cracking.
Like it or not, he'd best get cracking.
I'd better get cracking on that, knock on doors or something.
Pick the area that fits your current needs best and get cracking!
Time to get cracking.
Cynthia turned to her husband with a look that said 'don't pursue it,' then announced, If we're going to get in some ice skating, we'd better get cracking.