This is what I do (got it from kaplan):
For the PS & BS: (work through the passages in pairs)
Do the discrete questions first : spend 13 mins (clock will read: 57 mins)
Do the 1st 2 passages: 16 mins (clock: 41 mins)
the 2nd two passages: 16 mins (clock: 25 mins)
Do the 3rd pair of passages: 16 mins (clock: 9 mins)
you have 9 minutes for the last passage
-i don't worry about going over by a minute, because I usually finish another part I know better a little faster.
VERBAL: (again pairing the passages)
1st pair of passages: 17 mins (clock: 43 mins)
2nd pair: 17 mins (clock: 26)
3rd pair: 17 mins (clock: 9)
you have 9 mins for last passage
It helps keep you on track and from not lingering on a question too long.
good luck