What do people think are good economic policies to reduce informality?
Three part answer:

Causes:


Trust in the system (particularly trust in politics)
Attitudes to risk (i.e. being caught)/Enforceability of regulatory power
Education levels
Economic empowerment/unemployment/low wage level
Law of unintended consequences 
Cultural considerations
Geographical considerations


Reduction:


Political corruption cleansing
Tighter regulation on informality 
Greater communication and transparency
Demand and supply side policies


Evaluation:


Extent to which informality is a problem
'Trickle-down' effects
Ease in assessing magnitude of informality