Whatever method you use, the key to picking up a language is to increase immersion time with multiple sources and then maintain contact with the language. Ramp it up if you want to learn more or keep it regular to maintain.
The key to remember is that the human brain is terrible at learning material with no relation to anything else. That's why flashcards are one of the worst methods of learning, especially since languages don't always have one to one word mappings. Flashcards are only useful in providing foundation or reinforcement for other methods of learning.
Attend a formal structured course at a local community college to pick up the basics and keep you focused. Peer pressure is a wonderful incentive and having a teacher to direct questions/practice will help with nuances and culture (language is a reflection of the culture that uses it).
Buy a dictionary and find translations of books you've already read. Knowing what happens beforehand will help you pick up basics like grammar and vocabulary very quickly. However, at a certain level, you will notice yourself skipping the rest of the sentence because you picked up what's going on with the first few words. Start reading new books or the newspaper at this point.
Start listening to subtitled video. At first, you'll basically be reading off the text, but as you learn more from other languages, your ear will start to pick out words and phrases and depending on the translation, you might start to wonder who hired the monkey. At that point, drop the subtitles.
Music also works great because your brain will pick up the lyrics by association with the melody. Even if you have no clue as to their meaning, your ear will pick up the pronunciation. As you learn more vocabulary from other sources, you start to parse individual words instead of syllables.
Rosetta Stone is great because it lets you practice speaking, listening, and word association. However, it's limited by the fact it's basically static, so not as good as finding a fluent speaker and trying to hold a random conversation. It's primary benefit is picking up basic conversation very quickly (works well for vacations).
another thing is it helps cement the basics, but basically learning any language is incomplete without real immersion, which means natural speaking of some sort, somewhere. Doesn't have to be two-way conversation, just some way of getting a constant stream of conversation - often getting confused with a loss of understanding, but that is what helps drive learning by having a feeling of needing to learn what you are confused about. With repetition over time, it just gets driven into your mind.
Rosetta Stone uses a style that basically mimics learning your first language. Picture books with simple sentences, and if I wasn't in a Russian course right now, I'd be using Rosetta Stone. I feel like balancing both would just completely destroy my mind, but I'm starting to think I should start using Rosetta Stone again especially while I'm in the course - another source of Russian to keep the stuff in my mind.
Rosetta Stone I think is especially useful for Russian because it gives you visual references for the grammar basics, which there are many many things that have their own words that English basically compounds into a single word. A lot of clauses and propositions in English just get slammed into the words in Russian so it can be extremely confusing, and it's the prefixes and suffixes that give more meaning to a verb, noun, or adjective, and not the short connector words in-between like in English.
That's what keeps tripping me up, and memorizing/understanding the case endings and grammar specifics, even into 104 (now my second attempt in the course, and worse, after half a year of no Russian). That shit is just brutal to my mind.
Rosetta Stone shows you a picture and a sentence, and you can see, even in the first lessons, how the words start changing, and what short connectors mean.
I feel learning everything with an English equivalent is more harmful in the long run. To my visually oriented memory, it's helpful to have pictures in my head and be able to think in Russian how to describe that picture, instead of what a typical language course seems to call for, of which is learning direct or similar translations and trying to get translate in your head of what you want. At least, that's my case. Some people might be able to think of what they want to say entirely in Russian, even if it's incorrect, just the ability to think of the types of things you want to say in your head in entirely or mostly Russian, makes communication far more easy.
but courses are great because there is a lot of two-way conversation, so the instructor can help determine the problems.
But I have a problem that I still want to remember everything in English, so things I learn in class as corrections or new words that I want to know to make conversation smoother, I completely forget in a day.
It's the immersion that is always lacking, and some people are able to pick up a language without it, but I think I need to be dumped in Russia to really have a chance at getting anywhere near fluent.
but watching movies (with subtitles at first, then I'd say watch it again and again without), listening to music or good music videos that have a relation between the audio and visual elements, random videos... stuff that makes you mind constantly try and figure out what they are saying, especially helpful once you've got a basic grasp and are able to pick out a few words. In movies, you get the chance to possibly see things that connect with the words you don't know, or know the root words but don't understand the implied meaning.