It may be unrealistic to believe one could become fluent in a second language quickly-or even at all-but I wouldn't deter those who wish to try. Remember not to get discouraged if you don't progress as quickly as you would like, as we all learn different things at different paces. I've found that any language is simple once you've picked up the pattern, so my advice would be to find patterns.
I tend to learn languages on my own, as that is how my brain works, so my advice may not be so valuable as a teacher's, but I shall list below habits which have helped me to better understand and speak a new language.
1) Watching films in the language, with subtitles first, so as to learn new words, but then without so that your brain has to work to translate spoken dialogue.
2) Listen to music in said language. Not only is it good fun to discover new artists-new to yourself, of course-but it helps with pronunciation.
3) Speak to yourself in the foreign language as often as possible. Write your grocery lists, if you are the sort to write them, in that language as well.
4) Test yourself frequently without the aid of study materials.
5) Read books (comics as well, if you fancy) in the foreign language. This helps with grammar and spelling.
6) And, though it may seem obvious, find whichever methods suit your learning style. As I stated earlier, I learn best on my own and by finding patterns in things. Some learn best through communication; others learn through pictures.
I do wish you luck in your endeavors.