Scouting Opponent Tendencies
Mixups generally are unfavorable to the initiator against proper defense. In practice, no one can implement the Nash game-theoretic optimal defensive strategy. Moreover, there are not going to be enough interactions of that mixup in a game (even a longer set) for the distribution to really settle. Therefore, it is important to make quick, confident reads on your opponent's defensive strategy in order to improve success on your mixups.
The first "layer" is to scout your opponent's tendencies with the "pokes" of your mixup - low risk options that have limited low-risk counterplay, while likely being low reward and giving up your turn on block. It is important to find safe options that have limited counterplay first, since it allows you to safely use those options without worrying about getting blown-up, and to focus on the opponent and the defensive options they're trying to use.
Improving Mixup Success Rate
In theory, mixups are pure guesses. In practice, a player can improve the success rate of their mixups by influencing the defender's ability to guess correctly.
- Disguising the initiation of the mixup - take away the defender's ability to know that they have to make a decision - feints, cancels
- High speed of mixups - increase the decision making rate to fatigue the defender and lead to suboptimal defensive choices - poke into mixup
- Increase number of option presented - fatigue/load the defender's mental stack and lead to suboptimal defensive choices, counter reaction/timing based defense - more mixup options, rotating mixups