Orderly method of enriching one's bookmaker, maybe? (6)
I believe the answer is:
system
'orderly method' is the definition.
'system' can be an answer for 'method' (system is a kind of method). I am not sure about the 'orderly' bit.
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for system that I've seen before include "Method of organisation" , "Technique, method" , "Organised means of work" , "Method (for betting?)" , "Ordered scheme" .)