Clear the rubbish

Once the ground is visible, clear any rubbish on the surface or buried just below it - probe with a crowbar to find buried rubble. Not all of it has to be removed, but large items can block drainage, break the cultivator and stop you digging tree/shrub planting holes. So don't feel you have to clear the whole site - just have some idea of your planting scheme first so you can plan where you do need a good depth of soil.

Compacted and uneven ground

If the site has been heavily compacted by builder's machinery and feet (indicated by rock-hard ground and standing water after heavy rain), then you need to break up this solid layer with a pick, crowbar, spade or cultivator, depending on the total area and your energy.

Once you have workable soil, decide on levels and redistribute soil by hand or with a bulldozer to get an even surface.