How? What?

I really find it hard to think of things that I should write in my blog. The moment I write about some things, another idea will come up to my mind that lead me to changing my first thought. It was very difficult for me because I cannot start directly because of the different ideas that I cannot arrange. First, I thought of writing about the life of the Blessed Virgin Mary, then I decided to start writing about my faith and the Church. After writing few lines, I changed plan and i thought of writing about Lenten Season. Whew! I don't know how to start with it. I don't know how to arrange ideas so I could come up to a better blog. I mean a useful blog. How will i start it? What should be the first to be in my blog? These are the questions that I am struggling with right now. I hope somebody out there could help me in my problem. I badly need it.. Will you help me?