Preventing errors advice?

I am a nursing student and so far what terrifies me is how easily errors can occur in the nursing field. I might be exaggerating but I had times when I would be so nervous of making the simplest mistakes in my clinicals. I am starting to think that maybe nursing isn't for me because I do not want to harm a patient in any way! Therefore, i just need to know, besides the basic patient identification, what do you do to make sure errors do not occur? Or at least, any advice?