Thanks for all the great advice, people. A mentor of mine gave me some good business advice that applies very well to the domainer industry.
Never fall in love with inventory.
Domain names should be thought of like any other commodity... whether it be cows, corn, real estate, or widgets. If a domain is making it's reg fee in earnings, then don't be in such a hurry to sell... but don't ever get married to a name even if it does generate a little revenue for you. Even if you have future plans to develop it into a cool site. Decide whether you are a domainer or a developer. If you're a domainer than you can always find another name to brand your idea with. Never fall in love with a domain name.
I've learned this from hard experience. There have been many cases of someone offering me $xxx for a domain that wasn't covering it's reg fees but that I thought was particularly brandable. I rejected the offers. Then months later when reg fees start coming up, I'd email them to see if they were still interested in buying the domain. They rarely are, as they went with some other name that suits them just as well.
Don't reject an offer from an end-user banking on the hope that you'll get a better offer down the line. End-users are few and far between.
Also, just to rehash... here are my picks for the best tips from this thread :
SharonTucci : Try and not be a jack of all trades when it comes to domains unless you have incredibly deep pockets to begin with. Try focusing instead on a few areas.
MinionDH : Focus on cashflow. Instead of buying hundreds of names at reg fee - buy 1 solid generic name with traffic (preferably .com - be sure to avoid TMs).
Paxton : Try to get the highest possible rev share from your PPC providers. Sometimes all you have to do is contact your account manager and ask politely.
GiddyUp : Get creative with how you monetize your names - try all the parking providers - the difference can be HUGE. Don't be afraid to try out some affiliate programs out there. Parking Empire offers some great deals from the looks of it and I'm getting excited to try out (btw, no affiliation with them at all) Affiliate commissions will likely dwarf your parking earnings, even with a fraction of the clicks/traffic.
Centreurope : I would like to add an advice: identify the best sectors in English domain names & buy them in other languages. If I take the example of France, we are about 10 years behind the US. But the trend is more or less the same and it is easy to grab good domain names at reasonable prices and mostly with high potential.
Holdem8 : Once u have regg the domain, use a service such as whypark.com or 1plus.net to park your name. Then build some content there by hiring a ghostwriter in Elance to write a few articles or you can write those yourself. Remember, the going rate is only $15-$20 per article about 600-800 words. Submit your site to all search engines and remember to create a sitemap for better Google ranking. Then submit those articles with very good signature files to as many article sites as possible. You will start earning some $$ and not share the earnings with parking sites(sedo, namedrive, etc)...meaning better earnings per click!
Gazzip : When you get an offer at Sedo look up to see if any other extensions on the same name have recently been taken recently - If so, it gives you a very good idea of who may be making the offer. Google search the registrants name and you can find all sorts out info about them or their company.
Reece : Check resources such as NameBio and DnJournal. These provide a concrete sales history. USPTO.GOV is your friend -- remember that! Don't be a n00b and get into TM or typosquatting. You can make plenty of money in domaining without stooping to that level. 9. Traffic -- The big T! No traffic, no money. Easy as that. If you're name receives no traffic whatsoever, the only way you'll be able to generate income is by selling it. This makes it a less attractive option than buying a name which receives plenty of free traffic even when it hasn't been developed.
Domainbell : read the DNJournal.com religiously... every page on the entire site... and get to the new weekly sales report every Wednesday.... you'll learn what's selling for what by reading there... it's the most wonderful website for domainers on the entire internet.
Pseudo Mod : Believe me when I say domainers are not competition. They aren't buying because they are either broke or not interested in your domain, not necessarily because of you.
