In Agile environments (the majority) I would use the following to help guide me.
In non-agile environments I would still try and use some form of them
Agile Testing Quadrants
Determine where to do unit, integrated, user acceptance, performance, load and security testing
Testing Pyramid
Determine how to have a large number of unit and small number of integrated tests
HappySad Workflows
Use happy, sad and optional workflow paths
Continuous Integration
I would plan for a CI environment to run tests for both branches and master
Issue Tracking System
I would make sure to to use software like Jira, Pivotal Tracker, Trello, etc. to track issues
Improve through Continual Change
I would make sure to have some sort of retrospective system to constantly improve testing
Test cases are very important, but higher level practices should also be considered.