Missed Pill Dose: What To Do & Minimize Risks

Question
My girlfriend misplaced one pill and neglected to take a pill that day.  She commenced taking the pills after that day.  What is the safest way to deal with a missed dosage.  

Answer
As you hopefuly know, no birth control is 100%.  But when it isn't used in the correct manner, the risk increases.  So the safest way to avoid a missed pill is abstinence - but that's the safest way to avoid pregnancy all the time!  The next safest way is to use back up protection Until the next cycle begins.