In no particular order, a list of SVN Commands that I use most often. Note that these are command line instructions, if you need a GUI all the following are available in Tortoise.

svn info Shows which repository you are working in, and details about who committed last
svn st  Status of your current working copy
svn up  Update your working copy to match any changes in the repository. Your local changes are not affected.
svn commit  commit your changes to the repository