I have talked about Compost and the likes to loosen up clay soil, well if you have a bit of time before you plant out an area use Lime.
Calcium Carbonate or normal Agricultural Lime is a great breaker of clay soil, but with time.
Apply enough to cover the soil with a visible film and allow to be watered or rained in then apply again three times then leave for at least six months before planting and you will find the soil is easy to dig and the plants going into the ground will take off.
Please try.
Be Happy
Barry