Here are some useful links with GRAMMAR and VOCABULARY exercises at different levels:
http://www.english-4u.de/index.htm
You don’t need to suscribe. Just browse around the site to find extra practice on grammar, vocabulary, etc
http://www.autoenglish.org/freeexercises.htm
There are also some reading activities.
This site has great videos for BASIC GRAMMAR topics:
http://learnenglishteens.britishcouncil.org/grammar-vocabulary/grammar-videos
If you need to improve your LISTENING COMPREHENSION,
http://www.autoenglish.org/listenings.htm
http://www.englishcentral.com/videos#!/index/all/all/easiest/5 (Choose intermediate or advanced)
And here’s a podcast that you can download on your mobile phone.
http://www.bbc.co.uk/podcasts/series/6min
ONLINE DICTIONARY (very useful for online texts)