"I'd also appreciate any Russia-specific tips"
Learn the Cyrillic alphabet. If you do nothing else before your trip, do this. It will make everything MUCH easier, since you will be able to decode signs and sound out words. For instance, PECTOPAH is pronounced "restoran" and is, indeed, "restaurant."
I used the book Teach Yourself The Cyrillic Alphabet (it now appears to be out of print). This made it easy, as it broke it down into letter that are the same as English, letters that look the same but are pronounced differently, letters we don't have but sounds we do, etc.
St. Petersburg has a fair amount of English in the central section (the "tourist zone") with English menus and enough spoken English in restaurants and at museums to get the job done. I would assume that outside of this area, it's Russian or nothing (certainly the case outside of Moscow and St. Petersburg in general).
Make sure you visit the Russia Museum. The Hermitage is great, but it has stuff by artists you can see elsewhere. The Russia Museum has amazing things by Russian artists you won't see elsewhere; don't miss The Wave by Aivosovsky.
Make sure you visit the Yusupov Palace. I didn't get to Peterhof or the Catherine Palace, and they sound great but may be too blinged-out for my taste. But the Yusupov felt quite liveable (while still quite fancy); the little jewelbox of a theater inside the palace was wonderful.
If you have any interest in musical instruments or fancy mansions, or want to see something without crowds, go to the Sheremetyov Palace, which now houses a museum of musical instruments. The miniature violins and the armonica (not a typo; it's a glass harmonica) are still memorable to me, several years later, as is the Etruscan Room.
Other than that, your NYC skills will work well in St. Petersburg (taking the Metro, not showing your money in public, looking confident when you're going somewhere, etc).