Instructions
Defeat the Elite Four to get the first star on your Trainer Card. Your card will change to bronze. To defeat the Elite Four, you need a varied, high-level team. It may take multiple attempts because they technically represent the game's final boss battle.
Collect more than 200 Pokemon to get your second star. The card is copper in color. There are 386 different Pokemon to be found in Pokemon Ruby. Trade with friends who own Pokemon Sapphire, breed and evolve as many Pokemon as you can to hit the 200 mark. Check your Pokedex to see your progress.
Earn the third star by going to the Battle Tower (opened up after defeating the Elite Four and accessed by flying there or sailing in from Slateport or Lilycove City) and getting a 100-win streak. This is easier not easy. You need strong Pokemon, practice and a sturdy strategy to earn the third star. This star turns your Trainer Card silver.
Earn the fourth and final Trainer Card by winning each of the five contests at the Master Rank level. Before you can enter contests, you need the Contest Pass. Find this item in Verdanturf Town. After you complete this task, you will have all the stars on your Trainer Card. This final star makes your Trainer Card gold.