The Sign of the Cross (from the Fountain of Catholic Knowledge,
OFFICE OF CATHOLIC PUBLICATIONS, Imprimatur, 1877; and from THE
CATECHIST, by the Very Rev. Canon Howe, Imprimatur, 1898)
MAKING THE SIGN OF THE CROSS
The Sign of the Cross is a sacramental if we make it with the right
hand by touching the forehead (showing our belief in the Cross), the
breast (showing our love of the Cross), and the shoulders (showing our
readiness to bear the Cross). Sometimes a triple Cross is made with
the thumb for example at the reading of the Gospel. It is made on the
forehead, on the heart, and on the lips in order to show our readiness
to profess the Cross.
See also the Baltimore Catechism (1064).
Q. 1064. How do we make the sign of the cross?
A. We make the sign of the cross by putting the right hand to the
forehead, then on the breast, and then to the left and right
shoulders, saying, "In the name of the Father, and of the Son, and of
the Holy Ghost, Amen."
It is worth noting that the sign of the cross (for a Catholic) is a sacramental1.
That isn't how it was always done
The above sequence is comparatively new. The previous tradition had lasted for over a thousand years.
The early Church Fathers attested to the use of the sign of the cross.
Tertullian ((De corona, 30, ~ A.D 250) described the commonness of the
sign of the cross: “In all our travels and movements, in all our
coming in and going out, in putting on our shoes, at the bath, at the
table, in lighting our candles, in lying down, in sitting down,
whatever employment occupies us, we mark our foreheads with the sign
of the cross”
As described by Pope Innocent III2 it includes an explanation as to what each motion signifies. This is how the Greek Orthodox still do it: head, breast, right shoulder, left shoulder.
D.D. Emmons offers an explanation
For more than 1,200 years most Catholics made the Sign of the Cross in
a like manner — that is, people in the Eastern and Western Church
touched their forehead, their breast, and their shoulders, going right
to left, with three fingers. Before he became pope, Innocent III wrote
in The Sacred Mystery of the Altar, “The Sign of the Cross is made
with three fingers, because it is imprinted under invocation of the
Trinity… so that it descends from the upper part to the lower, and
crosses over from the right hand to the left because Christ came down
from the heaven to the Earth and crossed over from the Jews to the
Gentiles.”
By the end of the Middle Ages, however, Western Catholics were making
the Sign of the Cross using the hand in place of the fingers and
touching the left shoulder first. Among the sources documenting this
method and the rationale is a 15th-century devotion used by the nuns
of the Brigittine Monastery of Sion in Isleworth, England, which
stated that one should begin with the head and move downward, then to
the left side, and then to the right. The devotion supported this
form, saying that Jesus came down from the Father (forehead), was born
as man (breast), suffered on the Cross (left shoulder), and ascended
into heaven to sit at the right hand of the Father (right shoulder).
This method became the standard in the Western Church. It is not clear
why the changes took place or why they did not also take root in the
Eastern Church, which continues using three fingers to make the Sign
of the Cross and from right to left.
Anglicans are "a Western Church"
The Anglican confession uses the same form as the Catholics (see the origin of this practice, per Emmons). (The source is a current website article written by an Anglican Pastor, Greg Goebel3).
How do I make the sign?
The hand and finger traces Christ’s cross upon one’s head, heart
(center of chest), left shoulder and right shoulder. In the East it
is right, then left shoulder. In some traditions, the finger is kissed
after making the sign, or returned to the heart. When a priest or
bishop is blessing the people, he makes the sign as if signing them.
This means that rather than signing himself, he moves from their left
to their right.
1The characteristics of sacramentals
1668 Sacramentals are instituted for the sanctification of certain
ministries of the Church, certain states of life, a great variety of
circumstances in Christian life, and the use of many things helpful to
man. ... They always include a prayer, often accompanied by a specific sign, such as the laying on of hands, the sign of the cross, or the sprinkling of holy water (which recalls Baptism).
1670 Sacramentals do not confer the grace of the Holy Spirit in the
way that the sacraments do, but by the Church's prayer, they prepare
us to receive grace and dispose us to cooperate with it.
2 (Innocentius III, De sacro altaris mysterio, II, xlv in Patrologia Latina 217, 825C--D.)
3 "Greg {Goebel} is the founder of Anglican Pastor and serves as editor and one of the writers. He is an Anglican Priest of the Anglican Church in North America."