You have to complete all the tasks below.
It's really hard to complete it. Try your best.
An added bonus is that if you get at least four stars in your Trainer Card, The nurse at any Pokemon Centre will remember you and treat you like a VIP every time you request for healing. Not ground-shaking, but hey, its something special.
Ruby + Sapphire
FireRed + LeafGrean
Emerald
Diamond + Pearl + Platinum
Heart Gold + Soul Silver
Black + White
If you could do all of that... AWESOME! You are pretty much the master of pokemon!!! Good going tiger! But if you didn't... thats ok! But try your hardest! At least try to get 1 star. For color of your pass go to http://bulbapedia.bulbagarden.net/wiki/Trainer_stars
First what you have to do is complete the elite 4. Then you have to find all the pokemon in the whole region to get your 2nd star. After that if you catch all the pokemon in the whole region you will get your 3rd star. Your 4th star you get is for traveling every where in that region. And the 5th star you get is by beating the whole game. Thanks,this is what I did and I got all the stars.
5 stars
The stars are located on the top of the card on Pokemon Ruby or Sapphire.
The stars on your trainer card have absolutely no use whatsoever except for showing off to others. The stars also change the color of your trainer card.
In Platinum, you have to beat the Elite Four, win a Master Rank Contest, win 100 consecutive battles in the Battle Tower, capture 50 flags in the underground and catch all 493 pokemon.
To get stars on Pokemon platinum here is what you have to do... get 50 flags underground win 100 battles in a row at the battle tower beat the Pokemon league 10 times
to get stars achieve the following: beat the elite 4, catch all the hoenn pokemon, catch all the johto pokemon, catch all the kanto pokemon.
The black card is your trainer card with I think 5 stars
there on the back of your trainer card when you get all five stars you'll be more respected and nurse joy will change too
In outer space after getting 5 (five) stars on your trainer card.
coffin flags ARE American flags, so there's the same amount of stars on each.
you have to beat the elite 4, winning a master rank super contest in any of the categories, capturing 50 flags underground, and obtaining data on all Pokemon in the national dex excluding Mew, Celebi, Jirachi, Deoxys, Phione, Manaphy, Darkrai, Shaymin, and Arceus.
when you get four or five stars, go to the Pokemon center and the lady there will say: 'Hello, welcome to the Pokemon Center. We restore your tired Pokemon to full health. Would you like to... Th-that Trainer Card! That sparkling colour! And all those stars! I've seen several trainers with Silver Trainer Cards up to now... but you're the first to top them off with that Trainer Card. Please, (Players Name), may I have the honor of healing you Pokemon?' Then you say yes. Then she will say: 'I will be pleased to take your Pokemon for a few seconds.' Then the same old stuff.