It is hard to practice and improve your writing skills at home, but Cambridge have come up with a fantastic solution. They have developed a system called Write and Improve which comments on your text and lets you know what needs to be improved.There is a short video about this tool on the Cambridge website which may be of interest to you.

http://www.cambridgeenglish.org/learning-english/free-resources/write-and-improve/

It really is a fantastic tool for learners so have a go. Let me know how you get on!

There are also some useful videos on Youtube which explain different ways to improve your writing. You may want to check out Learn English with Emma [engVid]. She has a section on writing as well as many other things

Some other pages where you can find activities to improve your writing are

http://learnenglishteens.britishcouncil.org/skills/writing-skills-practice and

http://www.esolcourses.com/content/topicsmenu/writing.html