God has been sending me great literature the past month that focuses on this principle/discipline. If you haven't read Radical by David Platt, you should pick up a copy. Here's a link to a great article about the early church's views on simplicity, caring for the poor, and not turning simplicity into legalism. And last, I was given a book by Richard Foster, The Freedom of Simplicity, by my good friend at the beginning of summer that I am going to start reading this weekend. I'll let you know about it when I get finished.
I don't exactly know how simplicity is going to look in my life, but I know the Lord will show me! I will end with a great quote by Clement (this is taken from the article I linked):
"The handmaids of Christ should love simplicity. Simplicity is the forerunner of holiness. It smoothes out the inequalities of property. A holy ornament should surround your wrists, the joy of giving and the diligence of the housewife. On your feet should glitter untiring zeal in well-doing, and walking in the ways of righteousness. Your necklaces and chains are modesty and simplicity. Such jewelry comes from God's workshop."