On-line:
There are all sorts of sites that set you up with partners for pen pal/voice exchange/video exchange. The dominant languages people are wanting swaps for are Spanish and Mandarin, a lot of french also. You can find German, Italian, other languages on these too. They require extreme patience finding someone who'll carry on after a few language swaps/lessons but it can be worth it. A large chunk of these people are school/college/uni students wanting it for obvious reasons. Another large group are the professionals abroad they may be teachers, doctors who want better English. I found that particularly in Italian it's hard to catch people as they often want evening chats after the superduperlate italian tea time. The psychology of it is interesting, many people are too shy or other reasons to really jump headfirst into this learning method. It tends to work best when people are at a similar level in both languages so people don't feel too guilty. One party often ends up why the other one wants help/wants to learn the language if level is too different.
Duolingo is of some use.
One of my partners for Italian used to use an on-line class to learn English. He decided talking to me was better and cheaper.
If you're interested in Italian I'd actually recommend youtube and
OneWorldItaliano. It's done by a woman called Veronica who started doing them about 2-3 years ago, it's snowballed and she now has thousands of people that watch them and dozens of small lessons. The lessons are somewhat smarter laid out than the critic thinks they are. She's had the sheer damn determination to write and act out with these things and stay with them and I think they are great. They are numbered from 1 onwards.
Not on-line:
I just learnt on my own and learnt how I needed to learn. Started with a collins grammar book for a few quid, then CDs such as Paul Noble and Michel Thomas, parallel texts (my god they were so boring), harry potter in italian, trying to find shows then trying to find people to practice with!!!!!
One of the issues I had in learning Italian was I came from the creative writing generation at school and so was never taught any grammar, so in learning Italian I've learnt huge amounts of stuff I didn't know about English but already known my whole life. I learn quite well reading/writing too, that's one of my preferences.