One thing you should remember is to not to rush into filming effects. As you said, you only learnt it yesterday and now you're already filming. A good sign of when to film an effect is when you oare confident in performing the effect with real spectators.
That aside, the Ego Change itself was actually done fairly decently. It's okay to cover the majority of the card, but try to keep the fingers as open as possible so that the change is as visual as possible. Also, work on your clean up... Use the all around square up move to cleanly square the deck and finish the move.
Here is a clip of myself performing it. Hopefully this should help you

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One major thing you did is flash completely on the last clip. Do something about it... take it off, refilm it, just don't show that last clip.
Finally, welcome to the forums!
Steve
