Just to correct everyone interested in this topic, the correct term that should have been used is.... How do you mix MORTAR..?? Cement is only one ingredient in the mix not the whole mix, its like asking how to bake a flour when you really mean how to bake a cake..........just saying....and for the record above ground 1:4 ratio mix, below ground 1:3 ratio thats 1 part cement to 3 parts sand... the use of washing up liquid helps prevent the mix from drying out to quick but is infact against building control regulations, so ok if its a small diy job but not if your building a proper structure.....you can buy plasticisers from local builders merchants to add to the mix as an alternative to washing up liquid....