My favourite is immersion, like if you go to French class and your teacher gives you a sheet with a bunch of phrases and you can only speak to them in French, though the most effective is likely repetition.

Most fun : learning words/sentences here on Duolingo ; Most effective and fun : having conversations with native speakers :)

I have an amazing photographic memory, and am practically the dictionary when it comes to spelling; even when I hear the word without me seeing it before, so my best language learning style is for sure hearing it once, repeating it a few times, and then remembering it long term.

Repeating it over and over can get boring with others, but langauges are sometimes an exception.

Immersion and games; like learning through things you like to do. Immersion with music, TV, movies... writing! it's all fun and great. And effective.

Most enjoyable: Watching television, especially game shows, and especially those with vocabulary components. Think about what someone learning English would learn from Wheel of Fortune, for example. They say all the letters, lots of numbers, and form words!

Most effective: Actual conversation. While also the most nerve-wracking, it is also the most rewarding. That feeling you get after having a nice conversation using a new language is priceless.

The most effective method is to put yourself in a situation where you absolutely need to use your target language to communicate and you cannot simply switch back to your native language when you get into difficulty. When the brain regards using a language as a necessity rather than an intellectual game, it tends to retain things a lot more efficiently.
Of course, the best way to do this is to travel to your target language's country (which is hopefully one in which English-speaking isn't too widespread), but even just in terms of talking to people from language exchanges on skype, etc., deliberately choosing those with the very lowest level of English will force you to do more work in this regard.

(Obviously I'm assuming that you will have acquainted yourself with some fundamentals of grammar and vocabulary through books, Duo, etc. before doing this, although how much depends on your own confidence in yourself.)

I really like the Michal Thomas method, the course is like a conversation I tested other for a few hours before settling on Michal Thomas method.

Duolingo is great for learning to read and write but to be fair I did not do comparisons against other courses.

The combo seems to be working well, I just need to commit more time to both.

My most enjoyable method is going to an evening language course once or twice a week with a good teacher and a good group of students. So I can also make friends and have fun.

That's the way I learned german, spanish and esperanto when I was younger. (There is a very good and cheap language school in my city with a program of more than 12 languages).

I like to travel a lot in Europe (mostly Eastern Europe) and I always try to speak the local language. Let's say I'm goint to spend one week in Latvia. Since there is not always a teacher available, the most efficient method for me has several steps :

• learning the basics (hello, thank you, etc) with a conversation booklet and asking the locals (waiters, reception desk, clerks at the tourist info, etc) how to say this or that. They are always eager to help and it is a good way to make contacts

• going further with basics and "standard phrases" on different topics from www.loecsen.com (a fantastic website). At that point I begin to understand some grammar and can already practice the language in usual situations.

• If I am interrested in the language or the country and plan to return, the third step is finding a series of good podcasts with transcripts on the internet that I can listen to while going to work. There are many but finding a good one that suits me is sometimes hard (I found very good ones in hungarian, russian and greek).

• the fourth step is going to Duolingo on a (almost) daily routine to put some structure in what I already know and learn more grammar and vocabulary. At the same time I watch internet TV in the language I am studying. I like popular crimi series that are translated and dubbed by good actors, so I can watch the episode in the target language and then watch it again in french or english.

• the next step is reading books. At first, translations of books I have already read, then other ones.

• the final step is going to the country again and again to practice.

I don't think I can get it down to one favorite per category because my levels in the languages I'm working on are so different, and the resources available differ.

For languages that are similar to ones I already know so that I can have a pretty good comprehension level, I like listening to podcasts. Undoubtedly, this is effective in increasing comprehension, but I don't find it perfect for vocabulary building because I often have trouble making out the words I don't know, so I think reading would actually be more effective on that front.

I'm quite motivated to obtain a thorough understanding of Russian and Latin grammar, so I really appreciate translating sentences into them, for which ideal venues are the Duo reverse tree and a Memrise course very much modeled on Duolingo respectively. I greatly enjoy this, it's also very effective. Immersion on the reverse tree was wonderful for this when it existed; translatihan.com serves as a replacement for the languages it has. Alas, Russian isn't one of them as yet.

When I'm focusing on increasing my Russian and Latin vocabulary, I mostly use LingQ and a side-by-side text respectively. A lot of full-bore classical Latin is still a bit much for me, so having the translation right there really helps. I also both highly enjoy these and find them quite effective. I really want to understand Russian on a level so as to be able to easily understand news broadcasts and the like, but what I lack is the vocab, which something like LingQ is very well suited to help address.

My favorite would be taking classes over skype to prepare to volunteer somewhere I would need to use my Spanish. I knew I was making mistakes but I walked away (from the volunteer event) thinking about how cool it was that I talked in Spanish and was understood.

Most effective I'd have to say audio courses. I completed language transfer and that helped a lot. I did the first month of pimsleur awhile back want to go back do it again. I'm also really enjoying duolingo stories.

For me the most enjoyable and effective language learning methods is speaking. This is the most under-practiced skill in most language courses, yet it makes learning quick. It's one thing to passively translate or listen to Spanish, for example. It's quite another to actively have a conversation - non-scripted and not bound by the subject you're studying. You need to study, of course. But don't neglect speaking! It forces you to speak on the fly and it's better than studying. I speak Spanish fluently now after joining a meetup group to talk Spanish several times a week. I'm pretty dangerous in Italian too! Same reason. Get out more and have fun!

I would have to say repeating vocabulary at work. I don't know anyone personally who speaks Italian so I can't really practice with actual conversation. I would love to though! I feel like until I get to that point I need to really nail my basic vocabulary.

Off topic, but why are you learning Portuguese? I'm doing Spanish because a lot of people speak it where I hail from.

Reading. It's definitely the most effective way to expand your vocabulary, just like reading in your native tongue.

Conversing in your target language is fun and is absolutely necessary to truly master a language, but is not the main goal for me.