During Advent, I will be reading Advent and Christmas Wisdom from G.K. Chesterton, which I bought from my local Catholic bookstore. I had found Chesterton a bit hard to digest in large doses, but thought this book looked quite understandable and inspiring.
There are other Advent and Christmas Wisdom books out there that are sure to inspire you during this Advent season.
The Rosary is also a perfect spiritual practice for Advent--especially the Joyful Mysteries. I am currently reading Fr. Dwight Longenecker's Book Praying the Rosary for Inner Healing, which takes us on a journey through the different times and issues in our own lives while we pray the rosary for healing.
The most complete Advent resource I've seen is Ignatian Spirituality's Advent Resource page. They've got lots of links to articles, podcasts and an Advent calendar.
Pinterest has lots of wonderful DIY ideas for Advent-related items. Stop by and get those creative ideas flowing! (One that caught my eye was an avante guarde Advent wreath made with a vine, candles, and old silver pieces.)
Saint Louis University has very well thought out resources for each Sunday based on the readings for Sunday Mass. I think it is important to ferret out such resources, especially when the quality of homilies varies so much from parish to parish and often, priests do not focus on the practical application of the lessons from Scripture to everyday life. Stop by their website during Advent and feast on the wisdom of God's word. (Click on the arrow to the right of the drop-down menu to select the particular Sunday in question.)