Act Like You Give a Damn
If you're an improviser or improv student, you'll get plenty of tips about how to do scene work. You'll get them from directors, instructors, teammates, friends, family...me....
Before you decide which exercises to try, which philosophy to embrace and which guru to idolize, you might want to decide once and for all what you think an improviser is. Different people, venues and teams have different ideas about that.
For me, an improv performer is part actor, part game theory expert, and part magician. Let's focus on the acting.
I believe that, above all else, you need to seem to care. Every moment you are onstage — in a show or rehearsal or class — needs to be important to you. Or at least, it needs to seem important. When you are improvising, forget that it's "only" comedy. Think of yourself as performing (or rehearsing) Romeo and Juliet. Think of your director as someone you respect, and whose approval and guidance you value. Think of your fellow improv actors as artists you respect, and whose efforts you will support and mirror.
Act with emotion. Act with intent. Act with dynamic range. Act with intensity (intensity can be loud or brooding or violent or joyous). Act as though you are doing Shakespeare. Act bravely. Act by reacting. Act by repeating. Act by listening. Act as though you know that emotion comes from motion, and motion comes from emotion.
Act, in other words, like you give a damn. Like you give a damn about your craft, your partners and your director. Most of all, act like you give a damn about yourself. Your pride. Your impact on others. Do this, and audiences/colleagues/directors won't be acting when they give a damn about what you do.