Make sure you start off by reading the Paradigm Explanation page.

This strategy guide will provide general Paradigm recommendations for each of the fights including bosses, difficult side quests and each of the Missions, but are there specific tactics you can utilize once you have a feel for the Paradigm system?

Here are some things to consider that can help master the system:

1. ATB Refresh
   Learn and make use of the ATB Refresh Tactic. This is the quickest and easiest way to use Paradigms to your advantage and greatly increase the amount of output for your characters in each role and in each paradigm.
2. Focus on Offense
   The great thing about Final Fantasy XIII is that there is no punishment for getting KO’d during a fight. You can try, retry, and just keep trying again. Because of this, there’s no need to play it overly safe. As referenced in the Common and Recommended Paradigms section, try to focus on using the more offensive options over their defensive equivalents.
3. Party Member Roles
   Not all party members are created equally. In addition to some party members gaining access to certain roles earlier, your party members have strengths and weaknesses that make them better/worse at certain roles. Here are some guides you can use to learn more:
   • The Character Overview section
   • The Optimized Party Guide page
   • The Best Party section
4. Understand Role Bonuses
   You should have a solid understanding of the Role Level Crystals and the Role Bonuses that they provide to the character and their party members. Understanding and using these bonuses effectively can help you optimize your party.
5. Watch Your Party
   Remember that Saboteurs and Synergists will stop casting spells once all buffs and debuffs have been applied. You don’t want to have any of your party members just standing around, so swap to another Paradigm if you notice this happening.
6. Using Shrouds
   Having trouble with a difficult boss or Mission mark? Don’t forget to use your Shrouds. Aegisol will cast Protect, Shell, Veil and Vigilance at the start of a battle while Fortisol will cast Bravery, Faith and Haste. Using these items means you can avoid having to spend time in support Paradigms buffing your party members.
7. Practice, Practice, Practice
   This last piece of advice is obvious and probably annoying to read, but practice does make perfect, and the more you play around with different Paradigms and role combinations, the faster and more efficient you will become at getting the appropriate actions out of your party members at the right time.