The idea of buying a domain, parking it, and having some big offer come in for it right away is really just that – an IDEA. Theoretically, it rarely never happens! Rather than taking your domains and just parking them, you should consider doing something with them to try and get traffic coming into them. With traffic comes revenue and even a small design with some revenue can sell for big bucks. Not only that, a developed domain (even if it’s only a few pages) which is making money will usually sell much quicker than parking it and hoping that an offer comes through. This is where MiniSites come in. MiniSites are websites that only contain a few pages, but have completely unique content dedicated towards relevant keyphrases on those pages. MiniSites can be made using a scripting backend like WordPress, or by using static HTML or PHP pages which is actually found to be most common.
Some companies, such as Thinker Web Design offer domain minisite designs for less than a couple hundred bucks each. By taking your domain names and developing them into minisites you can have enough content to pull good organic search engine traffic (which parked domains won’t normally do) and also display ads which will probably pay you more than having the domain parked would as well. If minisites are something you may be interested in doing with your domains then I suggest doing some more searching for them. You can find some great examples online and you can get these types of websites done extremely cheap these days!