A Ritual for Strength
This ritual is best done during the new moon. If the ritual can be done outdoors, that's even better to help connect with the energy of Artemis, but it's not necessary.
Decorate your altar with colors that represent strength and courage to you. I like orange and red for that purpose. Place an image of Artemis somewhere on the altar as well. If you can find incense or herbs that are sacred to her, those are appropriate also.
Purifying the space and yourself in the way you normally would, and then cast the circle and invite the elements.
Begin to meditate on Artemis, and all that she is. Imagine her dancing freely in the woods, tall, beautiful, and laughing, surrounded by her nymphs. Imagine her compassion as she tends to a woman struggling in childbirth, or watches over a young girl to prevent harm from befalling her. Then imagine her in her role as huntress, wearing a short hunting tunic with her bow in hand, arrow notched and drawn back. She appears strong, and will cut down anything that stands in her way. Begin to focus on this image of her, with her strength and determination, and then invite her into the circle.
Ask her, out loud or inwardly, to lend you some of her strength and assist you with things you would like to overcome.
Artemis, lend me the courage to be myself!
Artemis, help me see that with determination my goals are attainable!
Artemis, help me to meet challenges head on!
Artemis, help me to be unafraid of change!
Artemis, help me to realize my own inner strength!
And so on and so forth, depending upon your need. As you do this, keep holding the image of the strong and fierce goddess in your mind, and begin to imagine yourself taking on those traits as well. Visualize yourself as confident and courageous and able to take on anything. Raise power towards the goal of manifesting this vision. Then release, ground, and give thanks to the goddess. Close the circle as you normally would.