These are some sources which I found useful when developing my own knowledge of the Tarot Cards:
Biddy Tarot – whilst Biddy’s online course is incredibly expensive, she does have a very good online resource, including useful tips for learning, and a comprehensive card reference guide.
Psychic Revelation – contains a useful reference source for each card, made easy by the reference to various situations, such as Love and Work.
Aeclectic Tarot – the meanings section is quite brief, but this site contains the best online collection of deck reviews.
Fables Den – Kimberley has an absolute maze of stuff and she puts it across very well. My favourite is her YouTube series, starting with The Fool’s Journey