I run a website called unrivalledinfo and I have a Q about email marketing

[unrivalledinfo]

At my website we review different kinds of internet marketing and publish the results (over 90 co's to date), but one thing I would love to know is how to stay out of peoples bulk/trash folder when using opt in mailing lists, I understand its best to get them to agree to recieve mail from my specific email address but how do I get the mail through to make that possible in the first place. (I haven't reviewed companies who sell theses lists yet) This is pretty much one of the only areas I haven't tested yet.
Thanks any one that can help.