You can only enter the lottery in August via e-mail to get tickets during a season. See this link for details and the e-mail address: SNL tickets
Some tidbits from the show I attended:
• The overall set is fairly small, giving it a very intimate feel. There were lots of overhead lights,although most of the time the set was dark with only the area of the current skit being lit up. There were probably around 10-15 big flat screens with the show airing as it would on live TV overhead for us to watch.
• During commercials, the cast and crew move very quickly. It is so well organized, there was very little verbal communication, everyone just seemed to know exactly what they had to do. It’s a large crew with people everywhere. Because it’s a fairly small space, sets have to come down and new ones have to go up often. A lot of times the set would remain dark and the crew would use flashlights.
• Pictures are not allowed. There were people standing above the aisles making sure the audience adhered to this rule. Occasionally you would see some people in seats getting approached and reminded of this fact.
• The band was great and would play during the commercial breaks/set changes.
• During one scene, there was fake blood used which got on the set floor…and it took quite a while for it to be cleaned up. There was o guys just using paper towels until someone finally came with a mop.
• During the news scene with Seth Meyers, he made a joke where very few people laughed, he then says “i’m going to have to fight to keep that one in”. One perk of attending the dress rehearsal, you get a little something extra not seen in the final airing.
• There’s no signal for us to laugh. The audience was naturally laughing. The only alert they had for us was the applause. At one point toward the very end, the sign for applause lit up but no one was applauding… I think everyone was too focused on watching the stage and taking in the final moments.