What are the five things you have to do on Pokemon Diamond and Pearl to get the black trainers card?

Answer 1

Base - Red Card The first card you will have is the Rileyeric Red one which contains no Stars on it. You will see this a lot in the game until you have go to the Elite Four

#1 - Blue Card The next card that you obtain is Generally obtained through the defeat of the Elite Four. Once you have defeated them, you will have the next star, which for this scenario is the Blue Card

#2 - Bronze Card The next card that you obtain is Generally obtained through Contests. Once you defeat the Master Rank in all the Contest Categories; Beauty, Cool, Cute, Smart & Tough, you will obtain this card, in this case...a Bronze Card

#3 - Silver Card The next card that you obtain is Generally obtained through the Capture the Flag MiniGame Underground. Simply put, once you have completed this while playing with others, you will get the next card, in this case...a Silver Card

#4 - Gold Card The penultimate card that you obtain is obtained via the Completion of the National Dex. What this requires you to do is get 482 Pokémon registered as owned in your Pokédex. This discounts; Mew, Lugia, Ho-oh, Celebi, Jirachi, Deoxys, Phione, Manaphy, Darkrai, Shaymin & Arceus. This will give you the next card, in this case...the Gold Card

#5 - Black Card The Final Card is the elusive 5 Star Black Card. This is obtained last, in our example, it is obtained by getting 100 consecutive wins in the Battle Tower. By no means an easy feat. Once this is done, you will have maxed out the Trainer Card!

This was taken from serebii.net all credit goes to them

For more information go to serebii.net ***you dont have to pass all the master rank contests but only one of them