Here is a MS Word version of the Russian Customs Declaration Form.
Usually these are filled out by hand, which can take a while. It’s nice to have a Microsoft, fill-able version that can be printed in advance. I cross borders often, driving my car, so I type in all the car information and print the form. This way, I don’t have to write all the car info every time.
This should be printed on A-5 paper (half of the standard A-4). You might have to fiddle with it, depending on how your printer is set up. Click on the link to download: A- 5 Russian Customs Declaration
Update: here is the A-4 Russian customs declaration form. These are now accepted at border crossings, and it’s much easier to print them on standard A-4 paper.