Well....by buying books of course! Below are a few great deals you should take advantage of:
Portrait of Calvin, by T.H.L. Parker.
A classic reference work on Calvin long out of print. Now made available once again by Desiring God.
Special price for today only (July 10, 2009) is $2.00
Tracts and Letters of John Calvin (Banner of Truth).
Seven Volumes. Also long out of print, this are wonderful short theological articles (tracts) and personal correspondence (letters) of Calvin. Banner of Truth is running a special for the entire year ($89.00), but it is slightly cheaper from CBD.
Sermons on Genesis 1-11 (Banner of Truth).
Available for the first time in English. Beautiful bound in typical Banner of Truth fashion.
The most valuable of all of Calvin's writings are his sermons. While I value his commentaries, his sermons are pure gold! If you don't read Calvin's sermons, you don't understand Calvin! Read these works and witness a masterful intersection of doctrine and application.
Sermons on Acts 1-17 (Banner of Truth)
Also available in English for the first time (sadly, the remaining portion of his sermons on Acts have been lost to history).
Truth for All Time (Banner of Truth)
A wonderful little primer on the Christian Faith. Though overshadowed by his later institutes, this little booklet contains core ethical and doctrinal Christianity. Also available in a paperback edition, but the gift edition is much better.