Traditional Worship is the style of worship that was fairly familiar to Christians for most of the Twentieth century, but it could encompass a great deal of variety.
The elements of worship would generally usually include prayer, music, Bible reading, and a sermon (homily). Other important elements that probably vary according to the occasion - and definitely according to the specific church or denomination - may be litanies, receiving of tithes and offerings, sacraments such as Communion, and a time for response.
Since the time when we began using the terms "Traditional Worship" and "Contemporary Worship," a lot of the focus has been on the style of music, and that is one major area of difference. Even Traditional Worship music could vary hugely from one congregation to another - from plainchant (real or imitation) and classical western music to "high church" grandiose music, gospel-style music, country music, folk music, and world music.
But another area of difference is that Traditional Worship tended or tends to speak more to the participant's mental perceptions and Contemporary Worship tends to speak more to perceptions of the physical senses (sight, sound, scent, and tactile sense).
Many churches that I have personally seen are now trying to use the best elements of each style of worship to provide the most meaningful worship experience possible for the people of their own congregations and communities.