Rule 1: Don't leap before you look. Seriously, who needs a good pair of pants?
Rule 2: Always carry a Swiss Army knife. You never know when you'll need to unscrew a clock.
Rule 3: Never leap into a time period without proper cultural sensitivity. Don't be that guy who wears acid-washed jeans in ancient Egypt.
See also: Rule 4: Leap only when absolutely necessary, and never on Tuesdays.
See also: Rule 5: Never trust a time-traveling companion with a mullet.