Okay well, my so called tips are quite obvious and hardly secrets. But I will share them anyway.
For one I use domain surfer, and overture to lookup the webmasters of particular domains. For instance if my domain is ChickenSoup.com and on Overture there is someone paying $.50 per click on the keyword "Chicken Soup" with the domain HomemadeChickenSoupRecipes.com ....
Obviously I will email that person to see if they have any interest. For two before I register any dot com, the .Net and or .Org extensions must be taken. Not only does this secure in my mind that there is a demand for the domain, but it also may lead to a quick sale and may cut out that entire first step. For three always realize your original investment was $7 (and some change). Be flexible in return emails. Accommodate there budget. If you can get a quick c-note or two. That's a 1000+% profit. For four, point all domains to an address. Do not let the domains remain dormant collecting dust and registration fees. Most end users are unaware of "who is" information. Therefore have no way of contacting you. Now I do not practice this technique. But soon will. However I have been fortunate enough to get several offers (about 10 sales in two months just through who is) out of the blue without any page. This is not recommended. But I do it, because Im not dependent upon the income of my domains. I have all the time in the world. And if I sell a domain? Good, I'll take my girl out for an extravagant night out on the town. But nothing more then that. It's not worth the effort.
Told you, no secret. Just lucky I guess....