If you like action/thriller/crime related series/dramas, then NCIS, Criminal Minds and The Castle will help you a lot. Mostly because they don't speak super fast (Criminal Minds for example). Also, they have different English accents so you can get used to listen different ways of speaking.

Something you can also do is, watch documentaries when you have nothing else to do, they speak fluently and at a average speed most of times, it will help you to improve your listening/understanding skills.

It is okay to learn more than 1 language at the same time, but you need to organize yourself to do it. Learning 1 language 2-3 days on the week, and learning the other one for 2-3 days too. Then the hardest or with less priority one, spend 1 day for it only. I'm a bit confusing but, my point is, for example: I want to learn Icelandic and Filipino, those are my main interest right now, but I also want to learn Korean and Japanese (or well, keep learning), but I can't learn all these languages at same time with an average IQ. What do I do? I fix my week schedule, from Monday to Wednesday I learn Icelandic, from Thursday to Saturday I learn Filipino (Tagalog) and on Sundays with less pressure, I practice sentences, questions, songs, words, etc in Korean/Japanese. Why only practice? Because I've learned the basics, and the most effective way for me to learn something is by repeating it many times a day, that way the next week I look at it, I'll remember if I did something or not, and if I did, then practice it for an hour or less, and test something new. Since there's always new words coming out, mostly made by trends or teenagers, is harder to learn a language based on books. With harder I mean, if you go to that country and you talk like you were some kind of robot (based everything on a book), people won't feel comfortable with it. Learning languages with young people or relaxed people is more effective, because they're almost always updated on how people talk in casual conversations, books and simple guides online will help you on how to speak politely I guess.