Heedful
Part of speech: adjective
Definition: taking heed paying close attention; mindful
Attentive
Part of speech: adjective
Definition: paying attention; noticing, watching, listening, or attending closely
Example sentence: Improv as an actor makes you present in the moment. You listen, you're attentive. You're not acting so much as reacting, which is what you're doing in life all the time.