I've done a Spanish course in my early 30s. I went to Spain, did a two week course there, four hours a day, very basic. The afternoon was free, although we had to prepare homework, which could be quite a lot if you wanted to commit to it.
Before going there I learnt some basic stuff: conjugations of being, having, doing, most prepositions, basic counting (1-100), some emotions and words like walking, seeing, right/left etc. The first morning they had a basic test and I could skip the first course because of my preparation. The first week was quite boring, just like being in high school, with stupid stories etc.
The second week on wednesday night we had a Sangria-tour around town. After several beers and sangrias I started speaking Spanish. Up til then my Spanish was mostly impaired by fear of failure, afraid to make mistakes. My teacher was there and I spoke to her for a half hour, of course with lots of help, searching for the right words, making many mistakes, but suddenly the fear was gone.
Russia: do the vodka tour! ;-) Laugh a lot and don't care about what they think. Listen to their English and compare that to your Russian.
I stayed in an appartment with other foreign students. Among eachother we didn't speak Spanish. You could stay with a Spanish family, and they don't speak English in general, so then you have to find a way. That will help a lot.
After these two weeks I've done two courses in my home town, and left it at that. Now when I'm in Spain I can speak Spanish after several days. I can manage in hotels and shops, have very basic conversations. My French has improved incredibly since then as well.
Disclaimer: in High School we had English, German, French, and even Latin and classic Greek, so I had a good basic knowledge and knew how to learn a language. It takes a lot of effort. After finishing high school my languages were bad and clumsy. After going on holidays I suddenly got to enjoy it. Doing a study where all books were English it all started to change.
Long story short: it takes a lot of effort. Do it all - traditional and pragmatic. Going to Russia is probably most effective.