Visa applications are completed online on the Russian Embassy website
http://www.rusemblon.org/

Notes:
Section 3: Patronymic name is the name from your father which you probably don't have, so just put down any middle names you have.
Section 6: write “tourism”
Section 7: leave blank
Section 8: write the name of a large city e.g. Moscow and a large town near your final exit point from Russia. This is likely to be Barnaul if you entering Mongolia through the Western border, and Ulan Ude if you are entering in the north (Sukhbaatar) border. If you are making a double entry list the town nearest you final exit point.
Section 9: put a day or so earlier than you think you will arrive otherwise you will be waiting at the border.
Section 13: leave blank

Contact Details
Embassy of the Russian Federation
Head of Mission: Mr Yury Viktorovich Fedotov
13 Kensington Palace Gardens, London W8 4QX

Office of the Trade Representative
33 Highgate West Hill
London N6 6NL
E-mail: info@rustradeuk.org
Website: www.rustradeuk.org

Telephone: (020) 7229 2666/3628/6412
(020) 7229 8027 Consular Section
(020) 7229 6451 Military Attaché's Office
(020) 8340 4492/1907 Office of the Trade Rep
Facsimile: (020) 7727 8625
020 7229 3215 Consular Department
020 7221 2038 Military Attache's Office
020 848 0112 Office of the Trade Representative