You do not. There's nothing you can do to make an audience know what you are thinking or feeling. IF YOU TRY TO DO THIS IN YOUR PHYSICAL ACTIONS, then that is what directors call "INDICATING." And they all hate that. It looks false. And if you have a director who is trying to make his show REALISTIC, then this is not what they want.
That does NOT mean that there are no thoughts or feelings in your actions. And some of those will be evident in your actions. BUT if you try to make the show thoughts and feelings, then it will not work.  THE AUDIENCE LOOK AT YOUR ACTIONS, assuming that you do something that is right and normal and natural for your character, and THE AUDIENCE WILL APPLY THEIR OWN THOUGHTS AND FEELINGS TO THAT ACTION. You do not have to do anything to make it happen. That is how audiences react normally.
This idea about "showing thoughts and feelings in acting" was how live theater used to be before Chekhov and Stanislavsky and all the others in the early 1900s. Actors would falsely show feelings through the set, prescribed actions. Look at some of the earliest descriptions of how to be an actor. And they did some of that in the original Russian theaters. But Stanislavsky and all his students and fellow directors and teachers did not like that. It was not real or true or even interesting.
In An Actor Prepares, the 1st Stanislavsky book, he tried to find ways to change the way old actors did that. So he and his fellow teachers/directors tried to find ways to counteract those false movements. That was where Affective Memory and other tools came from. AND those earliest tools were taken by some Russians to New York to teach to Strasberg and his fellow teachers at the Actor's Studio. BUT, this was wrong. Those Russians who went to NY left too early and got stuck in the Moscow Art Theater's very first experiments. In time, Stanislavsky's group discovered that those methods were not the way to make that work. When you study Stanislavsky's 3rd book, he had disavowed his earliest ideas about how to create truthful theater and, instead, had found that ACTION is really the only thing an audience will ever see. So by that time, he had already changed to pushing actors to focus on doing truthful actions, not worry about truthful thinking or emotions.
Chekhov had discovered much earlier that action is truth and emotions cannot be known by an audience. He fought Stanislavsky about this for decades. And Stanislavsky eventually agreed with him. In fact, Stanislavsky told Stella Adler, who had grown up in Strasberg's Method, that Strasberg was doing it wrongly and that she should look up Michael Chekhov because he was doing it right.
If you have read any of Chekhov's books or studied his lessons, it is clear that indicating thoughts or emotions as an actor does not work. You may well have thoughts or feel things while you are acting, but the audience may never see them. And, as an actor, YOU DO NOT HAVE TO THINK OF ANYTHING, OTHER THAN YOUR LINES AND ACTIONS AND MOTIVATIONS AND YOU DO NOT HAVE TO FEEL ANYTHING, OTHER THAN WHAT YOU MIGHT FEEL NATURALLY. But your feelings do not matter. It's the audience who has to feel something. AND they do that on their own.
Often, when a director says you need to feel something, he really means that you need to be able to cry on-stage and make it sound natural. This is a common requirement in acting, and you need to learn how to do it. What we teach is that you already know how to cry and it does not have to come from feelings. You already how to fake laughing.  Just imagine something really funny right now and start laughing. Quickly you will begin to feel the power of that laugh, which is an action you are performing, and you may then begin to laugh more spontaneously.  Laughing is a series of breaths. Start with a very long inhale and then let out a series of short exhales.    Crying is the opposite breathing pattern. Take in a very short inhale and then let out a series of long exhales. It sounds and looks like crying to the audience, And they will not care what you are thinking or how you are feeling, or why you care about crying. With practice, They will think you are crying and that is all you need to tell the story.