It's the most richly animated film yet--and by "yet," I don't just mean in the Pixar corpus, but in cinematic history. The flushed-down-the-sewer sequence is jaw-dropping. Digital is now transcendent.
2. Go soon.
Already in its fourth week, it won't be around forever.
3. Go late.
Choose the latest possible show--wife and I went to the 9:55--when kids are safely at home avoiding bedtime. The theater will also be empty enough that you can skip the previews and still score a good seat. The previews, for Daddy Day Camp and No Reservations, among others, are crimes against humanity.
4. Eat first.
If you go with an empty stomach, you'll end up cursing yourself, and your borborygmi will threaten to drown out the score. Ratatouille is the closest a neurotypical person will ever get to experiencing synaesthesia.