Eucharistic adoration is a practice in the Roman Catholic Church in which the Blessed Sacrament is exposed to and adored by the faithful.
Adoration is a sign of devotion to and worship of Jesus Christ, who is believed to be present Body, Blood, Soul, and Divinity, under the appearance of the consecrated host,
Adoration is worship called forth by God, and given exclusively to Him as God. It is designated by the Greek name latreia (Latinized, latria), for which the best translation that our language affords is the word Adoration.
Eucharistic Adoration is different from other acts of worship, such as supplication, confession of sin, etc., inasmuch as it formally consists in self-abasement before the Infinite, and in devout recognition of God’s transcendent excellence
A “Holy Hour” is an hour dedicated to Adoration. The one necessary thing is to be present, to be available, in the presence of the Eucharist. The Eucharist contains and expresses all forms of prayer: it is “the pure offering” of the whole Body of Christ to the glory of God’s name and according to the traditions of East and West, it is THE “sacrifice of praise.” CCC2643
There are many ways to practice being present. The Benedictines suggest a simple orderly approach and have published this printable PDF as a starting point.
If you are of high school age, here is a nice beginners guide for teens from our friends at Life Teen.
More about the St Clements First Friday Adoration Program.