the easiest way i think is having a great teacher for 3 months and then move to russia for 6 moths ! ! ! =) ... i want to do the same but with the english ...
if that is impossible, and you cannot find anyone who speaks Russian to tutor you, i would watch as many movies as i could in Russian, with no english subtitles, just straight russian language. and try to understand what they are saying. eventually (and i mean like after 100 movies) you might have an understanding of the language.
My Linguistics teacher said that Russian and English share a lot of structural similarities, when you get passed the cases. Based on the languages you speak (French, Spanish, Portuguese & English), they share a historical genetic relationship with Russian (Germanic/Romance/Slavic branches of the Indo-European language group), whereas Arabic doesn't (It's from the Semitic branch of the Afro-Asiatic language group, which includes Hebrew, Maltese, Amharic and Somali). After all that mouthful, Russian would be easier to learn than Arabic. Arabic is more widely spoken, but Russian is more of a lingua franca for countries in eastern Europe and northern Asia.