I agree with what Peachy said except that nothing will ever come close to immersion in a foreign country IF you don't speak your native language with compatriats while you are there. 

By far the skill that you need the most is listening and understanding. Eventually you will end up in a situation where you can speak, but if you don't have enough vocabulary and the ability to keep up with listening you could end up standing in the middle of a conversation with a couple of complete strangers while not being able to understand what they are asking you. I've actually done this a bunch of times and it's not exactly fun. There are now better ways! 

Italki is the place to be able to practice with a native speaker who will understand that you are just learning and will have patience, as you will have the same patience with them. You will be exchanging. 

You can get the benefits of immersion here. It's amazing actually. I can't believe this place exists sometimes. I feel so lucky! It makes me want to learn more languages. 

You can never do real immersion while you are still speaking English and I personally can't go too quickly back and forth between English and Spanish or it messes up my ability to understand and speak English well. When I'm in English, I'm in English and when I'm in Spanish, I'm in Spanish. I will think and respond in that language. I don't translate. Translation can make for weird sounding sentences in your target language.

Ok, that's enough English for me... I'm going to go and find a Spanish conversation now. :)  

You can befriend native speakers of your target language and talk to them on Skype on a daily basis. Connect with them through social media. Try to talk with as many people as you can. Have discussions with them like you would have with your regular friends. Make them a part of your daily life. The more connected you become with them the more you will feel immersed into their culture.

Find native speakers in your area and practice with them. I live in the United States as well and I have practiced my Spanish with hundreds of speakers without even leaving my state. The key is to look for them when you are doing everyday tasks such as getting groceries or even taking a walk. As long as the situation is right, you can just ask them if they speak Spanish and start practicing. If you've never done this before, it is probably one of the scariest things ever, but once you do it once, it will start to become fun. I like to call it leveling up(watch http://www.youtube.com/user/laoshu505000 with subtitles for inspiration). If you hear Spanish, you should try to practice with them. Also, watch Univision news and television shows and if you like the World Cup, watch it on Univision rather than ESPN. A lot of TV providers provide Univision as part of their regular package because there are many Spanish speakers in the United States. Also, look up the Latin Billboard Top 25 to hear the latest music. Basically, turn everything you usually do in English, into Spanish. Finally, when you are talking with people in English, translate their conversation into Spanish in your head. Hope I helped!

I've been able to reach fluency without ever visiting France - one thing I can guarantee you is that IT TAKES TIME! And immersion is possible without going to the country: find natives, speak, speak, speak with them or even better, speak with others who are learning the language - they've got the vocab you want to master and they're usually a smidgen more patient AND you won't feel nearly as self-conscious :) try meetup groups, clubs etc.

Also, surround yourself daily with the language: music, books, newspapers, even change your phone settings into your target language!

THINK IN THE LANGUAGE YOU WANT TO LEARN! 

¡Buena suerte!

Kiyama, I actually don't like those groups much because I want to learn Spanish from and chat in Spanish ONLY with native Spanish speakers so as not to start to think that my own lousy pronunciation and bad English habits might be right because I hear them coming out of others too. I want just only to have the native stuff coming in. I'd rather have 5 minutes with a native than many hours in one of those groups.