Since I have partaken on what will surely be a lengthy reading journey of the Catechism of the Catholic Church (CCC), I'll probably post on issues that this book addresses as I come to them. First stop: the place of Tradition (note capital T) within the Catholic faith. What's discussed here can be found in CCC 74-83.
Tradition is held at the same level as Scripture. The biggest reason is this: after Jesus ascended into heaven (Matthew 28 or Acts 1), the disciples at that time only had the Septuagint (Greek translation of the Old Testament) as their Scriptures. What they also relied upon were the words and teachings Jesus gave them during his earthly life, which they preached through the working of the Holy Spirit (Acts 2).
The Gospel has been handed down in two ways: 1) orally by the apostles and their followers and 2) in writing by such people as Paul and Luke (CCC 76). The oral transmission is what Catholics consider Tradition, while the writings are Scripture. The two are "closely connected" (CCC 78), for both share one common source. "Each of them makes present and fruitful in the Church the mystery of Christ, who promised to remain with his own 'always, to the close of the age.'" (Matthew 28:20, CCC 80).
As mentioned above, the apostles had only their Scriptures; the New Testament canon as we know had not even started forming! Thus, the early Christians relied on the teachings of Jesus as they were handed down from the apostles. The NT canon itself was not formed until the early 300s at the Council of Carthage because of the heretic Marcion. Thus, "the New Testament itself demonstrates the process of living Tradition" (CCC 83).
What then, is the difference between Tradition and tradition(s)? Catholic Tradition is the oral transmission from the apostles. "This living transmission, accomplished by the Holy Spirit, is called Tradition, since it is distinct from Sacred Scripture, though closely connected to it" (CCC 78). These are ideas and teachings that add to our rich Christian heritage and complement Scriptures, not detract from them. Other traditions in Catholicism are subject to change, such as priests being celebate (a possible, but highly unlikely example I know).
Part of this Tradition includes practices such as the seven sacraments, the order of the Mass, even baptism. Various doctrines such as the Trinity and how Christ is fully human and fully divine (2 natures in one person), things which Protestants hold to as well would also fall under Tradition.
This is why Catholics hold strongly to the idea of Tradition. Without a proper understanding of Church/Christian history, one would wonder why this emphasis is placed. But seen in its historical context, it makes sense why Tradition is important to the Catholic faith, and perhaps even, the entire Christian faith.