If you consider yourself an average-looking guy, it's natural to want to make a good impression on an attractive girl who shows interest in you. Firstly, be confident and carry yourself with self-assurance. Focus on your positive qualities and let your personality shine. Engage in meaningful conversations and show genuine interest in her as well. Compliment her on her qualities and achievements, but make sure your compliments are sincere and respectful. Additionally, maintain good hygiene, dress appropriately, and take care of your physical appearance. Remember that attractiveness goes beyond physical appearance, and showcasing your unique qualities and personality can make a lasting impression.