New Guy,
I agree with all of the replies so far...now my 2 cent...
Look at both sets of balls for runout possibility...
If you can runout, do so...
If you can't...
Take the set with the best probability and pocket what you can, then safety your opponent in such a way that they are forced to break up your problem balls, and/or give you ball in hand to do so yourself...
Sounds easy enough...but all billiard games are games of percentages...shoot the highest percentage shots within your ability...
Never force it...play defense and force your opponent to make low percentage shots, and/or give you ball in hand...
Never clear the table to a problem and be unable to convert, this turns the table to your opponents favor; ie less balls on the table makes more shots high percentage...
And always...keep it simple...draw patterns based on natural angles, take high percentage shots that are within your ability...learn defense...and exercise patience....
One of the players I admire most for simple play is Ralph Soquet, he makes it look so easy, never puts himself in position to have to do a lot with the cue ball, uses natural angles and speed control to knock 'em down.
Check Jimmy Reids site for pattern play and pointers:
http://freepoollessons.com/