If you want strategy for a particular format, play that format to learn
fight club isnt a proper format so stay out of there. make sure you play with no random so you learn to pill properly
If you ask me you'll get the most immedeate enjoyment out of playing in the daily tournaments. You'll be able to make by far the most credits there, and it is fairly competetive.
"No Random" is a gameplay setting. It is usually the default setting. The other is "Normal" which though misleading by its name is not preferred and very rarely used.
This you can set it at--- account details and preferences> your preferences>Game>I always want to use these settings to play:
Every mode has its own strategies. For me the most rewarding though are Tournies and Elo.