I'm with you on learning Spanish @coruscate, for the same reasons as you: it's a common language and I like being able to communicate with others.
My 2 cents on learning languages is that the best way for learning them is with comprehensive input, so basically live conversations, because it gives a chance to understand what is being said via context. But as I don't have anyone to chat with, I watch Spanish TV-shows. I started completely without subtitles, so I pretty much understood nothing except the few phrases I know, but the point behind it was to sensitize my ear to the language. Now I watch them with subtitles, partly because I got frustrated not understanding what's happening, but also hopefully to learn more from subtitles now that I'm better at listening.
On top of that I use Duolingo to learn words, phrases and grammar. I also try read something in Spanish every now and then, even though I understand little – it's all beneficial because the brain is unconsciously figuring the patterns in a language.
Thanks for all the good tips @celestal! Good idea to start watching TV as a way to immerse myself in the language. I've heard quite a few people mention Duolingo - so I'll definitely be checking that out!