Duff shares some good tips on how to get your Adobe PDF documents and presentations rank higher in Google and other search engines using simple techniques. Excerpts:

• Verify that each PDF file has a proper Description and file-name before you upload them on to the web. Open the PDF file in Adobe Acrobat or any Adobe Reader and press Ctrl+D to view the properties.
• Add structure and proper tags to PDF files to improve the quality and appearance of search results. Just like any web page, PDF documents add to the SEO value of your site when they contain keywords in prominent places and enclosed in heading (H1, H2) tags in the PDF files. Be sure to include links in the PDF files back to your own website. Users who post your PDF files on other servers will be posting links back to your own site.
• File-size limits may apply. Try to ensure that PDF files posted online are as small as possible, to minimize the chance that search engines will give up and fail to index the document. If posting large PDF files (due to the size of the included images, for example) and it’s critical that Google indexes all of the content, consider posting by chapter. This way, Google is less likely to stop indexing at, say, page 57 of a 112-page document.
• If you’re posting scanned documents, OCR them prior to posting.

From: AcrobatUsers.com