Vocabulary - Memrise and The New General Service List

This site   - Memrise .com gives exercises designed to help you learn the most frequently used words in English

To try this for yourself and earn your own points you will have to sign up to the site yourself at memrise.com
It is free so why not give it a go. It can also be used on tablet or iPad

Vocabulary development - Dictionary .com

This site-Dictionary .com is useful for learning:-

• the pronunciation of a word
• the words meaning
• syllabification of the word
• synonyms and 
• the word used in a sentence

Vocabulary

Vocabulary
This site "English Vocabulary Exercises" has a variety of exercises to help you develop both academic and general vocabulary. check out the weekly challenge exercises and visit this site often to increase your skills.

http://www.englishvocabularyexercises.com/index.html

Word based vocabulary games

Improve your vocabulary through the competative and fun games that you find here.  Word based vocabulary games

Develop academic and general vocabulary skills

This site give an excellent range of practice exercises for developing vocabulary skills.

Many kinds of vocabulary games

This site has a large number of vocabulary games available to help increase you skills. Check it out.

Gap fills and more

There are exercises here for both general and academic wordlists to increase you command of vocabulary. Each week this site will feature links to practise your English on various sites, with exercises to work on vocabulary, grammar, reading, pronunciation, and listening. Have fun!