I am a lay Dominican.
The four pillars of Dominican spirituality are these: prayer, study, community and apostolate.
PRAYER is no.1. It is the source of our spiritual strength. We pray at least the Morning and Evening Prayer from the Liturgy of the Hours (LOTH), and 5 decades of the rosary everyday. Daily mass is encouraged, but not required. Before I joined, I tried to develop the habit of praying the rosary everyday. I wanted to make sure that I can fulfill the obligations. It is not easy for someone who is working and who has a family to take care of. However, the promise does not bind under pain of sin, unless you are failing your obligation habitually or out of contempt; so if one day you fail to say the rosary or your Evening Prayer because you are very tired, then don’t worry about it and just pray again the next day.
STUDY - we are an Order of Preachers. We can’t put any substance to our preaching without study. You can continue studying St. Thomas, if you like. However, the chapter where you belong may have their own study program. The chapter may be studying the Vatican II documents, Church History, or the Bible. It doesn’t matter. But it will be in addition to your personal study of St. Thomas. Do not assume that all lay Dominicans will be talking about St. Thomas at every meeting. Not everybody in your chapter will be as interested in St. Thomas as you are, but that should not kill your interest in St. Thomas. I, too, love St. Thomas, and I study his writings whether the group studies them or not.
COMMUNITY - This aspect of Dominican life enables you to work with others in your chapter. The monthly meeting is one way that you nourish your solidarity with the Dominican family. If you have a common apostolate, try to join it, too, because it helps to build your community spirit.
APOSTOLATE - The preferred apostolate in the Order is preaching. But you can have other apostolate, like working with disabled or handicapped children, etc. St. Dominic preached and argued with the heretics in public. In the modern world some lay Dominicans assist in RCIA classes. Some teach catechism in schools. I do my preaching apostolate right here at CAF! I also have a website where I publish Catholic educational blogs. If you click my username at the upper left hand corner of this post, you will find a link to my website.
'Hope that helps.