Below are the links to various exercises you can do to improve your English. Some of them are based on this wiki (for example the vocabulary exercises) and some of them are general support for aspects of your grammar or academic writing.

Week 1 words
Week 2 words
Week 3 words
Week 4 words
Week 5 words
Week 6 words
Week 7 words
Week 8 words
Week 9 words
Week 10 words

Test Your Level of Vocabulary Knowledge - Go to this website to see how many words you know in the first 1000 words of English, the first 2000 words or academic words in English. Can you keep improving your score?

GrammarTalk - go to this website to read, learn and practice all the aspects of 'the' 'a' and the zero article in English. It is interactive, has lots of pictures and I think you will find it fun!