Onerous: Involving an amount of effort and difficulty.
You are going to learn three different color changes progressing from easy difficulty to very hard. All three are extremely visual and will require a couple minutes of practice, to a couple weeks to get down fluently. These three changes are challenging, knacky, fun, visual, quick, and most importantly they get reactions! The best part of all three changes? They end clean!
Pinch Change (Easy): A color change that happens in the blink of an eye, as you close your fingers over the face of the deck, the card instantly changes and you can hand the card to the spectator.
OHMM Change (Medium): A change that is meant to be done head on that can be performed fast or slow; either way it looks impossible to turn a card over at the finger tips and instantly turn it back around showing the change.
Bullet Change (Hard): The "knacky-ist" of the three, the Bullet Change happens faster than the spectators can react. Starting with a single card, it instantly changes, and immediately ends with a single card as you hand it to the audience.
Like any sleight, you need to practice these changes, and discover for yourself how to incorporate them into your card magic. Have fun learning, practicing, and performing!