I believe that practising the language by writing is a very important step towards fluency, because it will help you acquire a good sense of spelling, a better understanding of grammar and it will quickly alert you to any useful words that you need to express yourself.
At school, you probably can't avoid written assignments, but if you're doing self-study you have to make sure you write enough yourself. Then there are two problems:
1) It may be hard to think of things to write about.
2) You may not know anybody who can correct what you wrote, and penpals will correct you for so long. Even if you know people who could correct what you wrote, they might be uncomfortable doing so, because they don't want to offend you. (My personal experience with Asians.)
For these reasons I have created an online correction exchange for every language. You can find it at http://www.corectme.com . The site is free, so you can get free corrections there for whatever texts you wrote, and you can give back by helping people who are learning your language. And if you don't know what to write about, have a look at this list of interesting writing tasks!
I hope you will find this useful! Good luck in your studies!
