try these:
1. Directory Submission /Niche Directoy Submission
2. Article Writing/Submission
3. Press Release Writing/Submission
4. Social Bookmaking
5. Blog Writing/Posting
6. Classified Posting
7. Blog Commenting
8. Forum Posting
9. Link Building Activity
10. Document Sharing (PDF/PPT)
11. Business listing
12. Theme based links
13. SMO