Can one improve his/her english skills?
I believe that one can improve his/her english. Motivation is one of the key to the success of everything. If you are not motivated to learn English you will become frustrated and give up.
Set yourself achievable goals like doing homework, reading of books, newspapers, watching english shows, listening to english radio stations, learn new word everyday and put it into practice. Reading the papers can also expose us to the current affairs in the world and increase our general knowledge when watching english documentaries.

Improving english skills does not mean that we have to rely on long courses or tuition. Self study can also improve one's english. This is because of the self motivation within and the hardwork put in. Without motivation, the money put in for courses and tuition will be emiciated as the result will be fruitless. Thus it is possible for one to improve his/her english skills.