How can I improve my everyday language?

In my experience, the best way to learn to speak everyday English is to have a two pronged approach. A combination of television and literature will assist in teaching your brain the sound and structure of a properly formed English sentence. Reading will improve your vocabulary and spelling, especially if you take the time to look up the actual meaning of every word that you do not know the meaning of, in some cases it is easy to glean the meaning of a word from the context of the piece that you happen to be reading at that time. Television will help with the auditory side of your brain, in the sense that eventually your brain will automatically flag a sentence that does not sound right(as you form your sentence) which will help you deal with, among others, the various tenses when speaking English, i would recommend documentaries, or perhaps a lighthearted yet intellectually stimulating program like QI, previously hosted by Stephen Fry, currently hosted by Sandy Toksvic on the BBC, the program deals with a extremely wide range of topics and the language is impeccable, and of course one is thoroughly entertained while learning which makes the whole exercise less tedious, especially for a beginner. The visual stimulation that comes along with viewing a program such as the one mentioned above will also help with vocabulary because, again one is able to glean the meaning of words from the context of the discussion and the visuals. Of course speaking English when one has the opportunity is necessary to gain confidence and get some practice with pronunciation, but most English speakers would not correct grammatical errors in company as it might be considered rude or offensive so you won't perfect your language by merely speaking it.