Dedication is simply deciding to dedicate time (Usually a year and a day) to learning and following a path. I remember when I decided to learn more about Wicca. My grandfather had just died and of course death and the afterlife was on my mind a lot. I had to travel out of state to be with him in his final hours and attend his funeral.
Throughout my childhood my Grandmother is the biggest influence on Christianity for me. It always felt like she was worried more about appearances than what she actually professed to believe. Who cares if you wear a dress or jeans and a t-shirt? To her, it was unthinkable to not wear your "Sunday best". To her, going to church was a social event of the week.
So the weekend of my Grandfather's death and funeral, I chose the moment I viewed his body as my dedication. I had found a cross shortly before and had been wearing it in an effort to believe in Christianity. I kept looking at it, touching it, wondering if it was right for me. The moment I walked up to my grandfathers coffin and viewed his lifeless body, I knew my answer.
Because my grandfather was Christian, I left the necklace with him and made my decision to dedicate myself to Pagan study. I took more than the year and a day. It would be 5 more years before I actually decided I truly believed in Wicca.
Dedication doesn't have to be an elaborate ritual. Though you can certainly make it so if you wish! It simply has to be meaningful to you.