For me the three keys were pronunciation, conversations with native speakers and getting over the fear & self consciousness of those conversations.
It's useless to know what a word means if the person listening to you doesn't recognized the word. I experience that almost daily among Thais and expats for whom English is a second, third or nth language. The other major benefit is as you learn pronunciation, words spoken in the language will 'pop' from the incomprehensible flow. You won't know what the word means but you will have isolated it and that's a start. Teaching yourself and not surrpounded by native speakers? I've read the
International Phoentic Alphabet may help.
There are online language exchanges. Pair up with a native speaker of the language you're learning who is learning your native language. Uses skype. Some sites have suggested conversation topics for your learning level.
I believe in memorization of the most frequent words.
Spaced repetition software uses your accuracy on flashcards to show you the words you're having trouble with most often while the words you stone cold know won't be shown again for years. I use
Anki. Runs on Windoze, Mac and LInux, has some mobile versions, is free and under active development.
Some Spanish words have just stumped me because I get them mixed up with similar words. I'm trying something I read recently here
How to learn a language without using translations. My new flash cards have a picture of the word, e.g. a pillow, and on the 'back' of the card the spanish word. No English. I'll see if it helps. Can't imagine it wouldn't, as rosetta and native learning work similar to this.
Rosetta stone drove my left brain nuts. I couldn't squash to need to look up the words I knew, according to Rosetta tests, to see if I actually knew them. It was long and slow process, but I wasn't doing it there way. But the words I did learn are cemented in my brain. I may give them another try on my next language.
I started reading comprehension by getting children's books from the library.
Chrome browser has a tool that translates occasional words from English into your learning language. Haven't tried it.
Language Immersion for Chrome Teaches You a New Language While You Browse the Web
She'll hear something on a lesson and say "nobody says that, we say this...."
If they understand you, it doesn't matter (except maybe in France, if the stereotype holds true). Once you're routinely speaking with native speakers you'll pick up the slang, regional terms & accent, etc. Think about it. If you were approached by someone who pointed to your wrist and said 'Please, the watch say?' You'd tell them the time. (In some countries you'd also be likely to repeat the question in what you think is the correct form, with some form of attitude ranging from helpful to disdain.)