One of the best habits to develop as a graphic designer, digital artists, video editor, web designer or basically anything to do with a computer is to save your work. As obvious as this may sound you will be surprised at how often work is lost due to power outages or programs unexpectedly quitting. Those type of things are unpredictable so the best thing to do is to get into the habit of saving your work every two to three minutes depending on how fast you work.
Some programs have an "Auto Save" feature that I would suggest you use. Just make sure that you don't bog down your machine with a million versions of a file. Make sure you keep this in mind because in "crunch time" anything and everything that can go wrong will indeed go wrong. When was the last time this happen to you?
P.S. It will be wise of you to make today the day that you become a habitual saver.