Read through ReinH's Git Workflow for Agile teams here: http://reinh.com/blog/2009/03/02/a-git-workflow-for-agile-teams.html
This works very well for small teams. The goal here is to make sure everything that might be potentially unstable goes in to a branch of some kind. Only merge back to master when you are ready for everyone working outside of the feature branch to use it.
Note: this strategy is hardly git specific, but git makes implementing this strategy pretty easy.
