RCA is a good place to start (realtors commercial alliance)
As far as books there are plenty on development. The key is you will not have the contacts,knowledge,or clout to handle the big deals yet.
Go work for a commercial brokerage specializing in the area you want to have a niche in such as (retail,industrial,land,office,hotels,leasing,etc.etc.)
My training was on the job with a developer over 2 years working on a 150 million dollar project. In the field is the best way to learn but you need the basic foundation first.