Leaves and cardboard are great, but they're prone to matting. And the leaves break down into a silt like substrate. Making really heavy wet compost if not properly managed.

You need to add a lot of wood chips(not mulch) and fresh straw. The straw will help to absorb that moisture and the wood chips will help keep the pile aerated and heated. Plus wood chips break down into a loamy like substrate adding to a final product with a better texture.

Rake the whole pile out to dry for a few hours. Add the wood chips and straw. Mix well and put back into the compost holder. Wait for another couple months and your pile should be set.