(I'm running a paragon-tier Fourth Edition game, but these same concepts can be applied to other systems.)
Endurance tests can sometimes force the party to work together. I ran several "triathlon" and "decathlon" encounters (monsters - skill challenges - monsters - skill challenges) until the party ran out of daily resources. They were unable to rest between encounters, and so they started to realize they needed to conserve resources between fights.
I then hit them with a series of ambushes of varying complexities to train their ability to gauge individual encounters and how to manage resources when the circumstances of encounters were unpredictable. They've become much more conservative with daily resources, relying first on encounter resources and falling back on daily resources only when necessary, or as an expedient.
Currently, we're working on developing the team's ability to identify threats and focus fire to take out a particularly troublesome creatures (read: leader, healer, support, or otherwise tough character).
In our last session, the party had to take out three enemies with enormous amounts of hit points and high damage output, plus teamwork-heavy abilities. The party had to focus fire on a single enemy for several rounds to take one of them out, while they ignored others (even while taking damage from them) to make sure they could take each one out properly before they could heal.
If the monsters focused fire for a single round, they could take out any one party member, which they nearly did a couple times. Of course, the party I have already has a "protective" sense, that they will try and keep everyone conscious and fighting as much as possible. We've had a few character deaths, and they don't delay in making sure to get everyone on their feet ASAP.