We attended at least four of them over a 2 -1/2 year period before we selected our boat and we found Trawlerfest to be an excellent resource. No need to worry about looking like goobers, this is a very friendly group and there will be people of all different experience or non-experience levels.
If you don't have deck shoes, at least wear shoes that are easy to slip on and off as most boats will expect you to take them off prior to entering.
Climb all inside and outside walkways, even stand inside a shower if it has one to imagine usable space. Stand or sit at the helm and turn all around to notice visibility and sight lines. If you run into other folks that have recently bought or are in the search process, they also can be useful to chat with. You might take a small notepad to take notes because after a dozen boats and a hundred photos on your smart phones you'll be driving back home saying "hey which boat had that cool engine room access door....?". It might be worth it to write down the sequence of models you walk through so the photos make sense later. Better yet upon approaching a boat, make the first photo be of the brandname plate; then every photo will be of that boat in your sequence until the next brand name comes up (helps for reviewing later).
Saturday is typically much more crowded getting on boats so if you can go thursday or friday morning, you'll have less people to deal with.
Finally, assuming you're potential boat owners, the seminars are really useful so you might try for them next time if not on this go-around.
A couple of the best are "Boat buyers survival guide", and "What to look for before you call a surveyor".
Have fun and let me know if you have more specific questions.