Don't stress or worry about it. They will give some general comments on various topics first. At my session, they wanted to talk lots about mobile - something that could generate lots of traffic for some sites but will be difficult to monitize for many. After the general comments, they will then meet individually with site owners and look at your site. They dont have time to look at lots of different sites if you own many (because they meet individually with every site owner who attends), so they will want to look at your best one or two performers on Google adsense.

They dont have any magic up their sleeves. Most of the suggestions will be along the lines of things you constantly hear from them and can find on G's adsense website - Put your ads in the "hotspots" that attract people's vision, maximize the number of ads on your pages, blend colors of the ads and page background, make all of your ads accept both image and text. You do get a chance to ask questions, and the staffer I talked with was fairly candid and honest. They are helpful and supportive - no one will be telling you your site stinks.

Pick up whatever info you can get your hands on. I got an adsense policy booklet that they dont normally give out.

Talk to other website owners - networking is good.

I had to drive about 130 miles to attend my session - and I thought it was well worth it.

(From what I recall) The one I went to couple of years back had a seminar session with young energetic google folks running the show and talking about new exciting adsense products and features. Followed by break time with food & drinks. More talks and product overviews in the second half. You can ask questions during these periods but answers are generally brief.

After the official Adsense in Your City sessions you can have individual sessions with the Adsense team and they can go over your site(s) with you to help you increase conversions. The individual sessions are scheduled on a first-come-first-serve basis and made when you arrive in the morning. So if you do want the individual appt you should try to get there a bit before the sessions starts if your city is generally a busy one.

I wouldn't worry to much about stats. I didn't get a feel that these folks would pour into your stats in detail or even care. It was more "place a banner" here, increase "ad content" here, blah, blah. Nothing specific. Most of these folks were under 25-30 and seem fresh out of college.

Sorry your Adsense earnings are down. The upside is that if you learn one thing new there it is at least worth it and perhaps you may meet other publishers you can share something with.

Bring business cards. This is as much a networking event between publishers as it is a meet and greet between you and the AdSense personnel.

Find out what the parking situation is ahead of time. That way if it's tricky you won't be late or have to overpay for public parking. Some of the campuses (like the one in San Francisco) are located in areas that are inconvenient for parking.

They didn't even bring up my stats when I met with them although I'm pretty sure they review each account before hand on their own. Brought up my main site, looked it over, asked a few questions and said keep doing what you're doing. So, basically confirmation that I'm doing something right which was good to hear.

They covered AdSense in General, Mobile, and DFP (Doubleclick For Publishers) in a general sessions.

You can learn much from other Publishers if you take a little time to network...don't have to provide specific site information to learn something either.

Just relax and have fun. It's a good experience.