How you spend your time is more important than how much time you spend. Quality over quantity, we say. So, find ways to make study a part of your daily routine. Vocabulary on the bus, writing exercises at night, speaking exercises in the shower, etc. Unless you can make a language part of your life, they are very hard to learn. Talk to yourself in English instead of your native language. Complain in English when you're hurt or don't feel well. Little tricks like that can really improve your confidence and ability to use English. In short, study as much as you can every day without hating English. Opening a book and working through it is not the best way to learn a language.

I think consistency is the major factor in learning anything. You should spend about 2 hours daily to learn English. I think 2 hours are good enough if well spent.

Hmm, it's not really about how much time you spend, it's more about how are you going to spend it. I highly recommend watching some movies in English, with subtitles. It will help you a lot, trust me on that one. See you around.