"If you break the build, revert your commit immediately."It has surprised me how successful this has been. We are using Subversion (SVN) and while I thought that I knew how to revert a commit I found I learnt so much more about the powerful features Subversion offers to revert a commit. More importantly I, and I think others, are now much more comfortable/confident on quickly reverting a commit. This is empowering, it lowers cost/inhibitors.
I learnt Subversion can revert changes in a commit, even if not the most recent commit, without loosing the changes ... quickly. TortoiseSVN offers options like "revert from ..." which allow a change set of just the changes in that commit to be reverted by a following commit of the change set. If using Continuouse Integration (CI) it means that a revert is very low cost (lost work).
The team has found it very enabling. We can break the build but if we do the break is only for minutes. It does mean that we do need a fast build.
I've worked in companies with slow builds (hours). This experience emphasises the need to always have a fast build. It is always possible it is just a matter of finding how. The increased productivity of Continuouse Integration is significant.