The world isn't going to end if you break one of these rules by mistake. Its often taken to an extreme where you might feel terrible by crushing a snail unintentionally or by mistake or eating something with a little alcohol in it that you didn't know. This is not what the precepts are about. But it is what finding a middle balance, practicing awareness and being harmless both ways is all about.
It's easiest to just chose a day to be totally by yourself and follow these, but there are also temple days where you can go and do these. Look up your local temple and find out.
Intention is the cause of a harmful action, where regret or stress is its result. Learn your intentions before you act and don't do the things you'll regret. This is easier said than done, but only you can make this choice.
Doing this is being kind to yourself and to others, you don't have to do this for a lifetime (although you certainly can if you want), even if you do these knowingly for a few seconds, an hour or a day its worthwhile.
Mindfulness or awareness, as well as care and respect is most important - there lies the key. You can't follow these precepts without awareness of the precepts and what you are doing when you are doing it.