There's also a really helpful strategy that we found out not too long ago. You can create a contest in Steamgifts giving away a nice game that everyone would want, and ask for votes in return. Like this. Obviously you can't force people to vote for you, but in our case we noticed a really big boost because of this.
Pietro Righi Riva: I honestly have no idea. I think for us it helped a lot to have an animated gif the day that the game went up, because Fotonica is really a game that you have to see in motion. Although... at the time not many people were doing it, the gif thing, so I guess it is not very useful advice.
It helped that when we launched our campaign we did a Pay What You Want sale on indiegamestand.com, promising (or rather, hoping) to distribute Steam keys if we ever got Greenlit. That drove a lot of traffic and immediately pushed us to "80 percent to the top 100" (weirdly enough that's how Valve phrases your progress on Steam Greenlight), where we waited for a long while.
After that, we kept receiving 30/40 yes votes per day, and that kept our average steady until Valve started to accept bigger batches. I think it's crucial to have your Greenlight link in anything you do (press releases, features, blog posts, interviews, etc).
Giorgio Ciapponi: To get in the top places on Greenlight, what really matters is raw exposure to people able and willing to vote on Greenlight, in any form. This is probably mostly getting the gaming press to talk about you, unless you already have an established community around your studio or game.
We didn't have much luck with any of that, mostly because of our own inexperience in dealing with the press, and the niche genre our game is relegated to these days.
We had a couple of peaks coinciding with press exposure early on, but for the most part it's been a slow crawl with just a handful of votes per day, actually gaining positions only when a new batch of greenlit games was announced.
Davioware: Most of the advertising for my Greenlight campaign came from YouTube videos and Let's Plays or livestreams of the game, as well as articles on gaming sites. Many people seemed to think the game had potential, and went out on their own to write articles promoting it on Greenlight.
I just let the game speak for itself, didn't ask anyone to write articles, and slowly but surely the votes kept climbing until TowerClimb was a high enough rank to be accepted. The best thing you can do for your game is to get featured by popular YouTube channels, or get an article featured on popular gaming sites. Pretty obvious stuff. The more publicity, the more votes. Having a good trailer is essential, since those two minutes need to sell the entire premise and soul of your game.
Developers hoping to be Greenlighted
Ryan Creighton: I hope that Valve continues to meet indies one-on-one to find out about the sleepers and the diamonds in the rough. Spellirium showed well at PAX this year and found its audience. Those who like the game like it a lot -- they just may not be the people who sift through submissions on Greenlight. It's like any Ipsos-Reid poll you hear about. They'll say "40 percent of people believe this", when really, you're getting the opinions of 40 percent of people who answer surveys.
Ian MacLarty: I don't think Greenlight in its current form is a good system for developers. There's just way too much uncertainty. You don't know when or if your game will be Greenlit. I feel for developers that are totally dependent on getting through Greenlight. I really don't think I could face the uncertainty. It might be better if there were more regular and predictable approvals.
Ashton Raze: I think it has potential. I think there are a lot of ways it could be improved, too. Maybe a combination of an approval team and Greenlight could work. Or separate sections for finished games and unreleased games.
Antonio Iglesias: I think Greenlight was an interesting move by Valve, but a bit risky. It is not the best way to approve games for Steam, but I believe it is still an improvement over the previous process of sending an e-mail and never receiving an answer. I am sure Valve is already looking for other ways, but improving Greenlight is possible and could get it closer to an acceptable approval tool.
Colin Walsh: I think as long as Valve continues to take steps to improve the Greenlight process it will be beneficial, and assuming that they're actually accepting more games over time now than before Greenlight existed, it's probably already been a net gain overall.
I do feel that they could benefit from expanding their approvals team to help streamline the approvals process, with Greenlight acting as a recommendation system but maybe allow for otherwise deserving games that might get passed over by Greenlight for whatever reason to still have a chance to get accepted.
That said, I don't think they'll please everyone unless they open up the storefront completely like the App Store or Google Play -- but that has its own challenges that I think they want to avoid, because having a curated storefront is very valuable for Valve, for its customers, and for the developers who are already there.
Perhaps one solution to that, and it seems to be something that Valve may be working on, is to open up the purchasing/library/Steamworks part of Steam to everyone, to make it easier for developers to sell their games to people who already have Steam accounts, but to maintain the curated Steam storefront as they do today.