It has been a bit of an adjustment to get to the 20 for mythics. Thankfully my 10 man heroic(mythic now) raid guild were good friends with another 10 man heroic guild so we merged for the 20. We have been jelling through this first tier and almost set for the 20 man. We recruited a couple more raiders the last couple weeks to fill in needed spots after not recruiting for years. Took a little trial and error and trade recruitment spam. If they are interested in moving into that next step give them a shot, if they have issues on a farm night then move on and keep trying. Helps to be on a larger pop server too.
We also have other activities, mumble is usually active and fun, help each other out with invasions and the like, Friday night mount boss farms, alt raids, etc. to provide a bit more incentive.