Whilst the Enterprise Server architecture around CICS applications is different to mainframe CICS applications, the majority of the design principles are the same, and are discussed at length on the IBM Knowledge Center (http://www-01.ibm.com/support/knowledgecenter/?lang=en).
For existing CICS applications, performance can be improved by ensuring that the CICSECM directive is not set for non-CICS programs in your application. CICSECM enables the CICS preprocessor, which inserts additional code into programs, and having these set on non-CICS programs causes unnecessary processing.
If you work from within an IDE, the Directives Determination process ensures that the CICS preprocessor is enabled accordingly, but if you are working outside of the IDE, you must ensure the directive is correctly set yourself.