Although I’ve learned a decent amount of Mandarin, it will fade if I don’t keep on practicing. It’s difficult to practice speaking, since my Chinese friends in the Netherlands are very busy with their studies and the internet connection with the ones in China is often a bit shaky, but practicing reading, writing and listening I can do.
I have several different readers to practice reading, namely the Chinese Breeze (汉语风) series and the Reading China (中文天天读) series. They also have cd’s for listening practice, which I try to combine with watching Chinese movies. For writing I try to write in Chinese as much as possible with my Chinese friends on instant messengers.
If you also want to practice Mandarin, you should try to make friends with Chinese people. They can help you when you when you’re having trouble understanding something and can correct you if you write something wrong. I was lucky to have an internship in China where I made my first friends, but I found new friends in several other ways as well.
At first I looked on penpal sites, such as interpals.net but I found most on QQ. A Chinese IM service, similar to MSN Messenger. At first I was looking for new friends to help me, but I found that a lot Chinese students started adding me to practice their English, so I didn’t need to look too hard myself. You can also use WeChat, but I use that mostly to connect with friends I already have, so I’m not sure how easy it is to meet new people on there.