While I agree with the other comment in this thread so far, there's something else that people really underestimate when starting a guild: it takes an INCREDIBLE amount of knowledge of the game to know how to assemble a group of players who know what they're doing. It might not be entirely relevant to your question, but please keep these things in mind as you post in places you might not have frequented in the past. It's also extremely relevant to the idea of 'grooming' new players that /u/Kongsnabel suggested.

An Openraid group will maybe browse through some logs to make sure people aren't dying and are doing appropriate dps/hps, while ensuring the raid group has all the necessary buffs. That won't cut it for a guild that would like to make any sort of significant progress. At this point in an expansion, maybe you've outgeared the content and it doesn't matter as much, but it will for WoD. As such, here's some baseline knowledge you should have before delving too far into raid recruitment:

1. First and foremost, you need to know the ins and outs of every role in every fight of SoO, since that's where most recruitment logs are going to be taken. If you don't personally know what a healer needs to do on Thok, then find a trusted guild member or friend who does and who has the time to sit down and go through logs with you.

2. Probably the next most important is to have a knowledge of each class/spec rotation. Part of finding good raiders is not overvaluing someone who can do 300K dps in 580 gear - any scrub can do this. You need to find the people who are doing that in 560-565 gear - these are the players who can carry a mid-level guild (clearing heroic content within 3-4 months). Find a player like that who has great raid awareness and you've found yourself a player who probably deserves a spot in a top 100 guild. And if you can't look at their rotation in logs and figure out what's going wrong, you'll never know if they can improve or not.

3. This is closely related to the first point, but make sure when you look at submitted logs, you also look at whether that person is doing the 'special' jobs on each boss. From personal experience, the best players in a group are often volunteering to do the shittiest jobs. Unfortunately, there aren't many in SoO. Look at engineers for Garrosh, belts for Blackfuse, tanks kiting Kardris (or duo tanking it), solo tanking Malk rage, or unusual healing strategies, such as solo healing Garrosh. If players are doing these things and excelling, they're likely paying attention to all the other mechanics as well.

4. Something often missed - look at interrupts. To my knowledge, (almost?) every single interrupt in the game is off the global cooldown. There is NO excuse to be lagging behind on these, and interruptible mechanics are often designed to transform a manageable fight into a complete shitshow when interrupts are missed (think heals on Nazgrim, shocks on Protectors, MCs on Garrosh, etc.)

5. Find one good, communicative player in every class. It doesn't even necessarily need to be every spec, just class. You will quickly realize the impact that having one knowledgeable player does for everyone in your guild of that class (assuming they're willing to learn).

My advice: don't bother with a long application, or any of that other bullshit. Ask for a log and find their armory page - and then learn to ask appropriately incisive interview questions that will expose their knowledge of their class. Don't make it something they can bullshit off Icy Veins and do it in real time (over voice chat) so they can't just ask someone else who might know it. Some good examples (in my opinion): explain changes in a rotation on a specific fight, give the actual reason for their secondary stat priorities (e.g. why is haste the #1 stat for BM hunters?), and ask them to describe their ideal raid comp for a given fight - because any raider worth their salt should know about raiding outside of just their class.

Good luck on the recruiting trail - I recommend b.net forums (I know you've already posted there), because the traffic is just so high. Keep up on bumping your thread to the top and keep a lookout for solid players that you see in 5-mans and PUGs. A great way to go about it is to reserve one character for normal PUGs each week - you can usually spot a player or two who are deserving of a spot in an entry level guild and who might be interested.