tips for NOT getting pregnant

what are things i can do to ensure i won't get pregnant? any tips/tricks? (i.e. taking BC for X amount of months before i start having sex, whether i should double up on condoms or not, when in my cycle is the safest to play, etc) thanks! 
additinally: since it was mentioned in a comment, i'd figure i'd add i do NOT plan on having unprotected sex. thanks to all who have commented so far!(: