First you need to remember a few rules. 1) Never boil eggs directly from the refrigerator, because very cold eggs, which are put in hot water is likely to burst. 2) Use a timer – trying to guess how many boiled eggs, and constantly remind yourself to look at the clock is not worth it. 3) Never cook eggs too long (if you do not have a timer) – then the yolks will turn black and white like rubber. 4) If the eggs are very fresh (less than 4 days), cook them for 3 minutes longer. 5) Always use a small saucepan – when too many places, the eggs can bump against each other and crack. 6) Do not bring to a rapid boil; need to cook them over medium heat. 7) Remember that eggs a cushion to blunt end, which is going to air. While cooking it can meet the pressure and the shell is cracked. To avoid this, pierce the egg with the blunt end of a needle to come out steam.