It can be quite tricky to discuss things like income in an economy that's not really structured in the same way that we conceive of a modern economy. The majority of the 'households' listed in each settlement within Domesday are those of tenant farmers; these families would have both worked their own fields for subsistence, and paid their rent through labour on their lords fields. These are likely to have been subdivisions of communal fields worked in a rotation system, and the tenant's 'income' would largely be derived from any surplus produced from their own holdings.
As an interesting case study, we'll look at Wimborne Minster in Dorset, partly because my family lives there, and partly because it was a major Cerdicing royal vil and monastery, and a substantial settlement. In 1086, Wimborne is split into 2 estates, by far the larger of which is the royal estate. In 1086, Wimborne is host to 135 households, which works out as veeery roughly 6-700 people. For the period, this is a very prosperous rural settlement; Dorset is prime wool country with good agricultural land, and Wimborne itself is attendant on both the major minster church at St Cuthburga's and the royal manor at Kingston Lacy. Around half of the households are 'villagers'; these make up one of the largest classes of 'unfree' peasants, and the 'wealthiest' of the tenant classes, who hold much larger sections of land, with therefore greater opportunities for surplus. Another 68 are 'smallholders', with 7 'cottagers' who hold the smallest and least productive farms. These are likely to have been the more marginalised members of the community; Anglo-Saxon legal codes called, for example, for land to be set aside as a surety to provide for single mothers who were widowed or abandoned by the father of their children.
Notably rare in Domesday are Freemen, the wealthiest of the 'peasant' classes, and those who own their land outright rather than as tenant farmers from a lord. The proportion of freemen declines after Domesday, likely due to the rapacious tendencies of the Normans, but they are significantly more common in the former Danelaw. Debate rages furiously over why this might be. Theories vary from Danelaw freemen being the descendants of Danes who, essentially, stole the land and established themselves independently, to the Danes having 'emancipated' many of their tenants, to the Danelaw levels having previously been the case across the rest of England, but West Saxon freemen having largely abandoned their privileges during the substantial reforms and expansions of state power that dealt with the Viking threat of the ninth century.
What's particularly noticable in Domesday is the proportion of slaves. 15 of the households in Wimborne in 1086 are still slaves. Slavery had been declining steadily through the 11th century, and would largely disappear altogether by the 12th, but at the time of Domesday, around 10% of the population are still listed as slaves. These would have been mostly Welsh or Irish, and would have worked solely on their lord's lands, although slaves did still have some legal protection - from working on Sundays for example.
Tenant farmers would largely have worked communally; Wimborne had 45 'ploughlands' of which 5 were worked by ploughteams as labour for the lord, and 22 were worked by the villagers. As a major settlement, Wimborne had 8 mills, as well as 150 acres of pasture. These were home to the real cash crop, a flock of some 250 sheep. The wool trade was a mainstay of the Early Medieval English economy, and was extremely lucrative. Wool was not just ubiquitous within the domestic textiles industry but was also a major export, particularly to wics in the Low Countries such as Ypres. For the villagers of Wimborne, therefore, the wool trade may have afforded a relatively comfortable standard of living. The wealth of the settlement can be seen in the Norman Church; the original Anglo-Saxon minster church was a major institution, but was substantially remodelled following the Conquest into a large and intricate building. The neighbouring village of Canford still has most of its Anglo-Saxon Church, and it's frankly beautiful.