Congress is aiming to wrest back control of Punjab and Uttarakhand states, which are ruled by the main opposition Bharatiya Janata Party (BJP) and its allies, as part of a series of elections in five states that end in early March.
A good showing in all five would be a huge boost for Rahul Gandhi, the scion of India's most powerful political dynasty, who has campaigned actively for Congress.
The son, grandson and great-grandson of former prime ministers, Gandhi is considered likely to take over from the current Prime Minister, Manmohan Singh, but the timing is not clear.
A positive result may also provide breathing space for Singh's government in New Delhi after a year in which Congress saw policies derailed by opposition protests and its own allies, including a reform to allow majority foreign ownership of supermarkets.
Punjab, especially, is seen as Congress's for the taking. Ruled by an alliance of the local Shiromani Akali Dal (SAD) party and the BJP, the state has not returned an incumbent administration to power for decades. Punjab's economic growth has lagged and industrial development has stuttered.
"Congress expects to do well, and it probably will," said political analyst Amulya Ganguli. "And that will give it a big boost at a time when it is very down and out, with the economy slowing down, the government being accused of policy paralysis." "Nothing succeeds like success," he said.
In both Punjab and Uttarakhand, the Congress party has attacked its opponents on economic performance and on state corruption scandals - issues that have sapped the ruling party's support at the national level.
India's largest state, Uttar Pradesh, goes to the polls from next week and while Congress's chances there are not clear, it is expected to make gains from the last state election.
In Punjab, people were wrapped in shawls and scarves to ward off the January chill as they voted after weeks of campaigning where parties promised to continue subsidy schemes that have plunged the state into deep debt.
Punjabis were also offered cash and free liquor on the campaign trail, according to several media reports.
"With the state facing a ($16 billion) deficit, it is surprising how the political parties are announcing bonanzas, to every section of the people, from bicycles to girl students to sports kits for gyms," the Pioneer newspaper said in a recent editorial.
In the 1960s and 1970s, Punjab was a rare Indian success story. A star of the country's Green Revolution - an extensive farm reform program credited with ending famine in the country - Punjab drove growth at a time when India was throttled by the "Licence Raj," an all-pervading system of permits and quotas.
But after reforms in 1991 unleashed a boom in Asia's third-largest economy, Punjab was unable to capitalize, its industry hobbled by power shortages and soaring land prices.
"Congress should be able to form the next government as the people are fed up with the Akali-BJP government," said Naseeb Singh, 70, a farmer who voted in Banur, a small town about 25 km (15 miles) from the state capital, Chandigarh.
A spokesman for the Shiromani Akali Dal party said last week that Punjab would become India's most investor-friendly state once major power projects bore fruit.
In Uttarakhand, a Himalayan state bordering China and Nepal, Congress sought to capitalize on corruption allegations levelled against the former chief minister, whom the BJP hastily replaced ahead of the election. His successor is B.C. Khanduri.
"The clean image of Khanduri is a positive factor for the BJP ... though the Congress has a slight edge," said A.K. Chandel, a restaurant owner in the state capital, Dehradun.
