A good Novena prayer for St. Theresa is "My Novena Rose Prayer" or "St. Therese Novena Day One." Another good Novena prayer that focuses on Theresa's humility is "St. Therese Novena Day Four."
"My Novena Rose Prayer" asks Theresa to pick a flower from heaven and send it to the person offering the prayer on earth with Theresa's love. The prayer goes on to ask Theresa to help the person praying to believe in God's love as Theresa believes in God's love. The prayer also includes a time to ask for individual, unique requests.
Similarly, "St. Therese Novena Day One" tells God that he blesses Theresa because of Theresa's great ability to love. The prayer asks God to help the person praying to love children as Theresa loves children. The prayer ends by asking God to make the person loving.
Likewise, in "St. Therese Novena Day Four," the prayer talks about God's help to Theresa to live a simple and humble life. The person praying asks for help to trust in God. The prayer also asks for help recognizing the grace in kind acts of others.