Echoing advise from others, be relatively non-confrontational, enjoy the food nearby the stadium not in it, and bring lots of cash. Specifically here's some tips:
TRANSPORTATION
Make a decision early as to doing public transportation or driving to Levi Stadium. Driving almost mandates you purchase a parking pass in advance as all the stadium parking and the Santa Clara Parking Garage is off-limits to non-pass, drive up traffic. Folks without a pass have to use auxiliary parking from surrounding corporate office complexes. The closest are $50 cash, further away $50 credit/cash. There are bike cart transports from the farthest parking as it's about 1.3 miles from the furthest parking lots to the stadium, but that's $40 (not sure if credit is accepted).
Public transit options are VTA Light Rail from San Jose or Mountain View right to the side of the stadium. ACE Train for folks coming from Tracy/Stockton or Tri-Valley (Livermore/Pleasanton) to just across the stadium (5 min walk from the train stop to Tasman overpass right to the stadium). Take note the ACE train only runs one train there and one back. The train there gets you to the stadium just after 11 AM and the departing train leaves at a quarter to 6. This is an adjustment to last year where the arriving train got there just after noon, and the departing train left right after 4; no adjustment if the game goes into overtime. Even with the adjustment, not sure what that quarter to 6 departure is about.
Here's the schedule and the graphic outlines my point on the stadium bowl a bit further down:
https://www.acerail.com/Tickets/49ers/ACE-Train-Schedule
FOOD
Varied with general burger, hotdog, but also Thai, Mexican, Chinese, Indian food stations. High-end liquor stations as well in the general levels. The club levels are a whole different experience, like going from mall food court to Whole Foods. As is the pattern you'll identify by this point, you'll need loads of money. Personally, I start with a minimum of $200 cash to get you to this point.
SEATING
Most of the stadium seating is crap plastic seats of less quality than Candlestick. Club seating on all levels from about between the 30s is much better and has light padding. Almost like a general movie seat, but those tickets are dramatically more in price. The entire bowl has no overhang, so it's exposed unless the sun is to you back when seating. This means sun bearing down on you constantly and last year with no rain, fans were fortunate, but when it does rain there will be no protection like there was at Candlestick sitting under the overhang further away from the field. Locals hate it and complained right after the first preseason game last year, visitors also seem to hate it. It's laughable the 49ers thought this structure would at all compete with CenturyLink, oh and noise-wise it feels like a museum at times because most 49er "fans" retreat from the sun to the liquor stations opposed to rooting for their team. Listen to local radio KNBR and Damon Bruce who can pontificate on all these issues...
Overall its worth going to once, I've been three times, but highly likely you won't go back as I haven't either. Hope this helps some.
