Before Census returns, the best way is to check through the parish records for the established church of your ancestors. You can follow these back to the early 1500s. To go back further there are Wills, Hearth Taxes and many more ways to track people down in the UK :)
The firs thing you need is where where they in 1841, were they in the county of their birth? If not check the 1851 and to see where they give their birthplace.
Their are parish record look up exchanges for many of the British counties.
home of the Suffolk look ups