Good practice to use git together with svn

Subversion is just like container to contain git

Be sure to read the CAVEATS section coming with git-svn:

CAVEATS

For the sake of simplicity and interoperating with a less-capable system (SVN), it is recommended that all git svn users clone, fetch and dcommit directly from the SVN server, and avoid all git clone/pull/merge/push operations between git repositories and branches.
The recommended method of exchanging code between git branches and users is git format-patch and git am, or just 'dcommit’ing to the SVN repository.

Running git merge or git pull is NOT recommended on a branch you plan to dcommit from.
Subversion does not represent merges in any reasonable or useful fashion; so users using Subversion cannot see any merges you’ve made. Furthermore, if you merge or pull from a git branch that is a mirror of an SVN branch, dcommit may commit to the wrong branch.

So you can adopt any merge and publication workflow with Git, as long as you leave the SVN branches you mirror alone (in term of merges or rebases).

I've created a collection of how-to's and screencasts on how to use git-svn here:

http://www.tfnico.com/presentations/git-and-subversion

Among them you'll find a git-svn mirror setup. It's a bit of effort to understand and set up, but it's been working for me for nearly a year, with a fairly large SVN repository.

Update: An easy and valuable practice is to always initialize git-svn clones with the --prefix option. I've explained why here.