I assume you've seen the git svn crash course (http://git.or.cz/course/svn.html) which is good overview, but falls short on the subtleties of merging (particularly using git pull --rebase). The side-by-side commands in the two VCS it has is great. The ParrotVM wiki also has a git-svn guide (http://trac.parrot.org/parrot/wiki/git-svn-tutorial) that I've found quite helpful and has an introductory workflow.

(Alternately, it looks like svnimporter (http://www.subversionary.org/projects/svnimporter) can import ClearCase which gets at a tiny subset of your problem.)