To answer your original question 'where do you get most of your sales':
By far the most sales in my domaining history have been through emailing potential buyers. I'll add the caveat that we are of course talking about sales of substance; if it's just 'technically the most domain sales', I could say here on the forum. But my sales here have been mostly to 'dump' domains for a quick reseller price just because I don't want them in my folio anymore. But as far as the most sales of larger substance, it is through cold-emailing buyers.
The second largest number of my sales has been through people contacting me via my landing pages.
The third largest has been through people offering via Sedo. Then Afternic brings up the butt-end with my lowest number of sales.
Notes:
As others here have mentioned, whichever route you go, the most important thing is to have quality domains. Whether you email buyers or have a landing page or just list it for sale at a marketplace, none of that will get you a sale if you have the worst quality names that really don't help anyone with their business or online purpose. If they're low quality names but still have use, then you'll have very few inquiries (or none), you'll have to ask low prices, and you'll get very few sales. The higher the quality (the word 'quality' of course can spark an endless debate, but skip that right now), then the more inquiries you'll get, the more potential-buyers will respond to your emails, the higher price you can ask, and the more sales you'll get. - Treat those previous statements as a loose generalization, not a rule or guarantee
As for landing pages, I've tried a few different platforms that others above have mentioned, with various results. In the end I finally opted out of all of them and I make my own. I keep them simple, usually just a few words about the domain and what it can be used for - potential buyers already know their use, but it helps to throw a few more suggestions to strengthen their ideas - all the way up to a more detailed lander with more info. For an example of each: you can have a quick boo at Regiving (dot com), where I have just a few words. Then you can have a look at OkanaganLake (dot com), which I've put a more substantial lander on, to spell things out for any potential buyers in this area (Okanagan Lake is the most popular tourist-destination lake in British Columbia). But to build your own landers you need to figure it out yourself or hire someone to build them for you. I build my own, and use Photoshop to make quick logos and headers etc. A quick lander I can build complete in about ten minutes or less. I might work an hour or two for a more involved landing page. If you have hundreds of domains you probably won't want to go this route from scratch. Whenever I get a new domain or a few, I just do the landers right away, so the chore gets done in small bite-sized pieces.
As for emailing potential buyers, remember: only do it if you have genuine quality domains that you know - in your most sober and realistic and decent frame of mind - would help their online appearance and success. You know, don't email a stucco company for your 'BestStucco-ShopForQuality-Deals365 (dot info)' domain name because you have decided those are such fantastic keywords (plus it's got the '365' on there!!!) that they can really help increase the business of any stucco company!!!!! Please remember that I said 'in your most sober, realistic, decent frame of mind'. If you're emailing to sell Stucco (dot com), or StuccoSupplier (dot com), then yes technically you're still spamming, but you're spamming but with a quality domain that your potential buyer might actually appreciate and thank you for contacting them for. If you're emailing to sell the dot info I mentioned above, with the dashes and the 365... well, you haven't got a clue and you're the dictionary definition of spammer and no buyer ever wants to receive that email from you.
I would guess that the largest percentage of domain sellers don't even email potential buyers for their domains. They think 'if someone really wants this domain, they'll contact me'. But that is very very rarely the case. This is the usual case: most potential buyers of your domain actually never think of your domain. They don't think of domains, period, they don't think about yours, they don't know yours is available to buy, they don't know how to go about buying it or what they should pay. There, that sentence describes the overwhelming majority of the potential buyers for your domains. Keep in mind what the buyer of Chocolate (dot com) said: after he bought the domain (for some large undisclosed number), it made the news... and immediately, two large chocolate manufacturers contacted him and offered huge sums to buy the domain from him. - See, even the largest companies get settled into their usual operating mode, with their usual domain and website that they don't even think about, and then one day you come along with your (hopefully premium, helpful) domain, and remind them what's out there.
Basically, you nudge it into their consciousness. I email for my own domains, and I email as a broker for premiums owned by others. I have never, ever contacted any buyer who said "Oh, I've been thinking about that domain, looking for one like that." Emailing them is what nudges them to consciously think about your domain, whether it is premium or just 'good'. You know, if you own SoundCompany (dot com) (which I do), am I just gonna let it sit around for sale while all those dozens of businesses who have 'sound company' right in their domain name just carry on bizness without ever thinking about my domain... or am I gonna email them and nudge it into their thoughts? I emailed, got offers, but haven't got the offer that will make me sell it yet. Still, if I hadn't emailed... no one's contacted me out of the blue for that domain. Sometimes you gotta take it to the buyers, to increase the number of people who actually give your domain a thought.
There are a lot of different methods and tactics. Above is my own experience and .02 cents
