Walk Slowly, Look Holy
One who serves at the altar, whether as acolyte, crucifer, or thurifer, must always keep in mind that the attention of the congregation is not to be on those ministering but on the liturgy. Therefore, always move discreetly and quietly - and above all with reverence.
Posture
Standing: When standing, stand up straight, and if you are carrying a candle or the processional cross make sure that it is straight.
Kneeling: When kneeling, put all of your weight on your knees and kneel upright. Do not squat or slouch. It looks terrible!
Bowing: There are two types of bows: the profound bow and the simple bow. The profound bow is used at key periods during the service (see more). The simple bow, at the name of Jesus and on other occasions of reverence, is made with the head, inclining the shoulders slightly. One never bows when carrying a torch, cross, flag or banner.
Genuflecting: Genuflection (the bending of the knee) is a sign of reverence to the Blessed Sacrament when reserved in an aumbry or tabernacle or on the altar. It is done simply and with dignity. Don't make it look as if you are falling forward or crouching down! Standing up straight, bend your right knee until it touches the floor or gets clo- the left knee will naturally bend a bit - and keep your back straight. This will take practice, but, again, your actions are not to be a distraction to the congregation. One never genuflects when carrying anything (cross, torch, banner, etc).
Sitting: Sit up straight in the chair, knees together, feet together.
Position of the Hands
Unless you are carrying something, your hands should always be folded and held above the waist. They should never hang down at your sides or hang folded below the waist. When sitting, either fold your hands in your lap or place them straight out on your knees with palms down.
The Sign of the Cross
The sign of the cross should always be made reverently and in a dignified manner. You are signing yourself with the Cross of Christ; this act of devotion should convey that meaning. With your right hand, fingers together, touch your forehead first, then your chest, then your left shoulder, and finally your right shoulder. Keep the hand motions unobtrusive. The use of the sign of the cross by those serving at the altar is determined by the custom of the parish and the direction of the priest. A good general rule is that when the celebrant makes the sign of the cross, you make the sign of the cross; when the celebrant doesn't, you don’t.
Responses
One of your responsibilities is to lead the people in prayers and responses. Therefore, make sure you know them, and say (or sing) them audibly and reverently; don't rush and don't lag behind! Keep the pace set by the celebrant or the congregation.
Walking
Always walk slowly and with dignity when serving at the altar. Your movements should never appear rushed or hurried. But at the same time, stiffness must be avoided. Military steps, square corners, and quick turns are all out of place.
Direction of the Eyes
When one is serving, eyes should always be focused on the action at the altar, on the reader, or on the preacher. It is very distracting to have a server staring into the congregation or at the ceiling. If you don't know where to look, the best thing is to keep your eyes lowered and look at the floor.