First of all I want to tell you don't worry get sandboxed, I always use Directory Submission, Social Bookmarking, blog comment, press relise, forum posting after very soon ready of my site i do 2000-3000 directory submission, 500-700 social bookmarking and regular basic blog comment and forum psoting I ever never get sandboxed for any of my site becouse directory link need time to get approval the trick what you said 10 link per day you will far far away from your competator