Be prayerful! Make sure that as you're serving, you're being prayerful. The way you sit, the placement of your hands and where your eyes focus, can certainly impact the prayerfulness of the Mass. Your own demeanor, your movements and body language all can lead to a more prayerful experience.
Know the Mass! If you want to be the best Server you can be, learn about the different parts and aspects of the Mass. Become familiar with the church space and the items used at Mass. The more you know, the better you will serve.
Be a leader! As a Server, you are in front of the congregation, and in a way, can help lead them to a more prayerful experience of the liturgy. Your example at the altar does influence everyone's experience of the Mass. Lead with a reverent and prayerful example.
Ask questions! If you're not sure how to do something, ask your altar server coordinator or your priest. It's much better to ask and get it right, than to guess and get it wrong!