Don't rush your croissant folds like I did, unless you want hockey pucks.
I tried making croissants last weekend and skimped on the chilling time between folds. The butter melted into the dough, and they baked into dense, greasy bricks. It took me two days to realize that each fold needs a full hour in the fridge. Save yourself the trouble and stick to the timer.
Yeah I learned that the hard way too, my first batch could have doubled as doorstops. I got impatient and tried to speed up the folds, which just made a greasy mess. I'm pretty sure I invented a new type of building material.