You mentioned Erdnase, so obviously you're into cards. The question is however, these talent shows...are they close up or on a stage? This would depend on the type of effects you could pull off. Keep in mind however, that the allure to magic is not just "the tricks." It's the performance. Magic is art, it's theater, it's abandonment of the disbelief of the impossible for a short period of time. The best performances I have ever seen were performances in which even though the effect was so simple, the performance grabbed me and made me emotionally invested and I couldn't help but say "Wow...that was beautiful." Those performances grab the majority of your senses. They combine performance art, with magic, music and visual.
If everyone is used to you doing cards, and cards are your thing, maybe consider adding some stage friendly aspects to some card effects. For example, combining Toxic with cards (maybe as a closer) might be a nice touch. I actually described an effect in my book, called "Impossible Prediction," that combines a calculator, a little bit of mentalism and a card prediction that leaves your audience absolutely sure that there was no way you could have known any of it in advance.
You could also give a nod to the classic magicians that came before you by starting with a classy old school routine (tux/tails, some classical effects), with some classy/haunting music in the background. You could even begin by telling a short story before you perform any magic (not sure how much time you have). Something like; "Growing up I was inspired by magic and the magicians I watched on television. Before that, the birth of modern magic was created by the likes of Houdini, Cardini, Blackstone and others too various to name them all. It is because of these pioneers that I am standing here doing what I love. For a child, magic is the breathtaking journey into a fantasy world where anything is possible. I'm inviting you to take that journey with me this evening as I pay homage to those that came before me." The music begins to play, and you begin your routine. Start slow and progressively get more dramatic with more impressive/impossible effects until it culminates in something grand at the end. Make sure you remain silent through the entire performance and allow the magic and the music to narrate the "journey."
In a performance like this, almost every aspect of what you do, can be an effect. For example, perhaps you set up an end table sized table and begin setting the mood of a classical performance. You could do an appearing candle effect, place the candle in a holder on the table, light it, an appearing silk that can be used to dust the table lightly, removing a deck of cards from your pocket methodically and basically make a magic performance out of setting up your performance. Then move into your effects (cards/whatever).
An effect that has nothing to do with cards but can be drawn out to be a classy performance all by itself (and still use all of the above) is a Zombie Ball routine.
Some examples of music that would fit a routine like these:
Hope this helps
