This really is one of my favorite games to play outside, especially on a beach, with girls, at night, and lots of people.
Some stratedgies for ensuring all goes well:

Pick two captains and have them alternate picking teammates, this helps the teams to be as fair as possible.
Alternate strong link - weak link - strong - weak - etc for the best defense.
When you run to the other side always, always, always run in between the weakest link- darting off and "surprising" another link never surprises them and really only causes you to lose momentum.
When on defense it's always better to give and fall back than to stand your ground.
Along with the above stratedgy others on your team should be prepared to fall back too to keep the two attacked from being strained on both sides.

Also if you're running low on people it's easiest to omit the person picking someone to take back with them rule.