How to maintain code standards while developing an android app

If internet available then call webservice and result should store in SQLite db ,From Sqlite Db display data in RecyclerView, If internet not available then display data from last loaded sqlite DB. I leaned how to call web service and how to create local db and performing CURD operations on it.To complete this task i want follow some coding structure without doing randomly.Someone suggest me any reference to deal with coding structures in android app development.Book also fine.