There are a few key things to avoid when using a pressure cooker. Make sure you don't open the pressure cooker during cooking (it's not usually possible to open modern electric pressure cookers during cooking but it's important not to try as it can be dangerous). Don't release the pressure before the timer finishes to ensure that the food is properly cooked. Finally, don't overfill the pressure cooker, there is usually a fill line about ⅔ of the way up the pot.