Two or three steps one way to take the defender with you, then an explosive change into the other. The counter-movement is what turns standing around into getting free.
From a standstill you never escape the cover shadow — the defender is standing where he is standing for precisely that reason. The check-away flips it: you first move where you do not want to go, take the defender with you, then break into the space he has just vacated himself. Two mistakes make the movement useless. First, strolling through the initial move — if it does not look convincing, the defender does not follow and all you have done is drift a few metres. Second, the timing: you want to be free when your team-mate can actually play the pass, not three seconds earlier. Look at him and tie your start to his touch. And it is not about covering ground — a few metres and one sharp change of direction usually do it, and in tight space even less.