Ah, the lament of a Muscovite visiting the northern capital.
Although people in St. Petersburg speak Russian like your teacher in Moscow or Berlin, there are a few peculiarities of language use in the northern capital that you need to know. One is that the word ?…?»?µ?± only refers to black bread. White bread is called ?±???»???°, which means a roll in other parts of the Russian-speaking world.
And while we're on food: Moscow's ?????€???†?° is St. Petersburg's ?????€?° (chicken); it's not ???€?µ?‡???° but ???€?µ?‡?° (buckwheat groats) up north: and don't look for signs for ???°???€???° like in Moscow, but rather ???°???µ?€???° — called in other places doner kebab, kebab and gyro.
There are a few other words you might not understand. In St. Petersburg, if someone asks if you've seen his ?‚?€???±???°, don't look for a pipe. He means his cell phone, which Russians in other parts of the country and world call ?????±???»????????. And a mass transit pass called ???€???µ?·???????? ?±???»?µ?‚ down in Moscow, is ???°?€?‚???‡???° up north.
If you're using that pass to get around the city and visit friends, you should also know a bit about entrances. In the old part of the city apartment houses usually had two entrances. One was for servants and riff-raff. The more ceremonial main entrance is called ???°?€?°???????µ, from ???°?€?°?????‹?? ?????????µ?·?? (ceremonial entry) that somehow got turned into a neuter adjective with no noun attached. Sometimes they call it ???°?€?°?????°??. In short: if it sounds like a parade, it's the front door.
And finally, don't get confused by all the city names. First the city was ???°?????‚-???µ?‚?µ?€?±???€?? (St. Petersburg), named by Peter the Great in honor of St. Peter, not himself. During World War I, the name was deemed too German-sounding and changed to a Russified ???µ?‚?€?????€?°?? (Petrograd). A few years later, it was renamed ?›?µ?????????€?°?? (Leningrad) in honor of Vladimir Lenin who pulled off a revolution here. Since it was called that during the Nazi invasion and blockade, people say ?›?µ?????????€?°?? ?? ?»?µ?????????€?°???†?‹ (Leningraders) with pride and respect, even though the city is once again ???°?????‚-???µ?‚?µ?€?±???€?? (St. Petersburg).
How do residents deal with all this? Simple. They ignore most of those names and call their hometown ?????‚?µ?€ (Peter) and call themselves ?????‚?µ?€?†?‹ (Peterites), ?????‚?µ?€?µ?† or ?????‚?µ?€???????? for a man, ?????‚?µ?€?????°?? for a woman. For more information on these folks up in Peter, check out a song called ?’ ?????‚?µ?€?µ ?€” ?????‚?? (When in Peter ?€” Drink) by a group called Leningrad.