My parents wanted to raise us kids bilingual, so we grew up speaking Spanish, French, and German in our home. Spanish stuck with me as many of my friends were Latino/a and I retook Spanish and French in high school, using both in travels and in my work. German never stuck, although I've been known to respond to a command in German and have sung a few songs in the language.
In high school, I also took Russian before traveling to Russia for two 3 month long trips.
In college, I took Russian, French, Spanish, Italian, German, and dabbled in Mohawk Indian, Japanese, Tagalog, and Mandarin.
I really love languages. I also really love talking and traveling. I try to learn words and phrases before I travel, but also love picking up words from people around me. Maybe because I'm musical, I can pick up languages and pronunciations very well.
I think communication is a blessing so I try to learn ways to connect. My first time in Russia, with only 3 months of Russian language classes, my Dominican friend and I ran into an Italian man in Moscow and ended up communicating in some Spanish, some Russian, and some German and Italian words we knew from songbooks. It was a truly ridiculous conversation, but we were all able to understand each other.
My suggestions when immersion is not possible is to find conversational partners. Find a familiar book in the language you want to work on and also start to write in that language. When I was relearning French before a trip to Haiti, I bough a French-Creole Bible and had my daily quiet times in French. I kept my journal and wrote down simple prayers and simple diary entries in French. I read a few books in French (with my French-English dictionary in tow). When I arrived in Haiti, I accidentally crashed a pastor's conference and ended up talking with a French pastor, from actual France....halfway through our conversation, I realized OUT LOUD that we were speaking French. He replied, "but of course, we have been speaking in French for the last half hour." It was really cool!!!!