With difficulty but this link might help;

http://www.thegardenersalmanac.co.uk/Data/Soil-Clay/Soil%20-%20Clay.htm

Add all the humus you can find and some coarse grit. Even a mulch of lawn mowings , though they do deplete the nitrogen while rotting. If you have autumn leaves spread them on the lawn and mow them, and use the bits as a deep mulch over the winter. Empty all your used compost onto the soil. If it is acid clay a dressing of lime wouldn't come amiss.

I find this a never ending battle every year I add lots of home made compost and leaf mould both mixed with grit. The best way I find coping with clay soil is to plant clay soil lovers where possible as clay soil is rich in nutrients and a considerable range of plants will do very well.

Loads and loads of humus and grit added over the years will make the soil much easier to work. I collect horse manure as well and it all helps. Roses like clay... I have lots of climbers with clematis intertwining, all seem very happy on clay.

Isn't it nice when we all agree?

it takes years!! Lots of manure, compost, leaf mould. Mine is rather nice now after years of conditioning. But don't be put off, I see it as taming the garden!!

But you'll notice it's a little easier to work each year as long as you add stuff as above.