How do I manage collaborative development on a Drupal site?
It is a workflow change but you should get used to working on a fresh dump of the live DB. There are three ways to get changes into the DB.


Features. This won't work for everything but will for a lot of things you need.
update hooks. When features won't work you can hard code things into an update hook of a module you own. 
Manual changes. Use sparingly. Some things don't come naturally to features or update hooks and are just much easier to do manually. This is a last resort but sometimes is the only piratical way. 


If you can. Several times a day get a fresh dump and test your build, you should have less integration problems.