Continuing Work on shade bed

Yesterday I went out to work on the shade garden bed, as I plan to start planting in it this weekend.  We have below freezing nighttime temps for the next few days, but I'm crossing my fingers this is winters last hurrah.  My astilbes have to go into the ground, and I also received my iris plants and they are sitting here wrapped in plastic.  So, first I used all those rocks I have dug up to make a border, then I used my stand up tiller to turn the soil.  There is still a lot of clay.  I started just pulling out chunks and throwing them to the side.  I feel pretty frustrated with it.  Hoping it will improve the more I work with it.