fischi and SFO777 have done a good job with the basics. I'll add that you'll be absolutely fine. Just use usual precautions while around crowds.

I've found it difficult to find English speakers, but try to learn the cyrillic alphabet before you head over; indeed, it's not terribly difficult. Once you can recognize the letters, you'll quickly recognize words (some of which are very similar to English) and will be able to order off Russian menus by simply pointing to what you want.

I'm heading back in March, too -- I'm sure you'll enjoy it!