This will help you block mail containing words in the "Subject" line:
--------------------------------------------------------------------

1. Go to Tools, then to Message Rules.
2. Choose Mail, a new window will appear.
3. Click the Mail Rules tab at the top of the window
4. Click the New button on the right hand side
5. Check the box to the left of the line that reads
   "Where the Subject line contains specific words"
6. Next, you want to specify which folder the message will be moved to.
7. Check the box to the left of "Move it to the specified folder"
8. In the next box, click the line "contains specified words"
9. A new window will appear asking which specific words you would
   like to filter. When done hit OK
10. Next, click the line "specified" to select the specified folder.
11. Choose the correct folder then hit OK
12. The last step is to give the mail filter an appropriate name. 
    Type in the name in the box and then hit OK to save the settings.
13. Repeat as necessary for each mail filter you want to create.

If you would like to filter specific email addresses, you would check off "Where the From line contains people" or "Where the To or CC line contains people"