A question I can answer! I’ve been teaching this for the last 5 years. Most of my sources lay in textbooks unfortunately, but I’ve referenced primary sources where relevant. In short, most people considered the war to be over, and were looking for a brighter future.
A couple of things worth bearing in mind for your question:
the war had not actually finished by the time of the General Election. Although Germany and its European allies had been defeated (VE), Japan was still fighting (VJ). This led to the rather unusual scenario of Churchill having to leave the Potsdam Conference for the results of the general election, only to be replaced by Attlee halfway through
Churchill was Prime Minister from 1940-45 and 1951-55, but he only won one election (in 1951). He was chosen as the most palatable option for all sides in the emerging wartime coalition. Either you've asked this question because you've just seen Darkest Hour, or you haven't, in which case you should see it for a fairly good representation of the situation after Chamberlain was forced to step down.
Churchill was seen by most across the UK, regardless of political affiliation, as an incredibly capable wartime leader. His speeches have often been given too much credit for 'whipping up' the country during the war (the original radio broadcasts are suprisingly underwhelming compared to his later recordings/Gary Oldman's renditions). Regardless, he was considered a capable set of hands during the war. However, history has many examples of people that were good in war, and bad in peace, or vice versa. Off the top of my head, Carter was seen as poor wartime leader over Reagan after the Soviet invasion of Afghanistan 1979, credited as contributing to his failure to secure a second term.
There had not been a general election since 1935, meaning that there was a 10-year period in which the British public had not really been able to voice their views on the composition of Parliament. One key area in which Labour gained votes lay in the Beveridge Report, commissioned in 1941 and reporting in 1942. It found that British society was plagued by the Five Giants (squalor, ignorance, want, idleness, and disease). Parallel to this was the growing dominance of Keynesian economics since the Great Depression, which (very briefly) holds that spending is the best way to get an economy out of a depression. Churchill and most of the Conservatives held on to the previous dominant theory of Classical Economics, which held the economy to be largely self-adjusting, therefore wish to avoid large amounts of state interventionism. Labour in particular used this as the basis of ongoing support for the war, promising that after the war the government would reward people for their struggles and sacrifices. For his part, Churchill gave a radio broadcast in 1943 entitled "After The War", in which he promised more limited action on the Beveridge report, for example compulsory national insurance ('social security'), but was decidedly lukewarm on the notion of the NHS (free universal healthcare).
After VE Day (and before VJ Day), Labour refused to continue a wartime coalition, leading to the King asking Churchill to form a caretaker government in preparation for a general election. The Conservative and Labour manifestos were created, largely mirroring their attitudes during the war. One of Churchill’s biggest missteps was a speech given 4th June 1945, in which he stated that the socialist government that Labour was promising “would have to fall back on some form of Gestapo, no doubt very humanely directed in the first instance.” This was sharply criticised as being both fantastical, and disrespectful of the still recent war. While he did not claim to be opposed to the idea of the NHS, the Conservatives did not promise to enact for the next parliament, with only vague promises years down the line.
Attlee’s government won the 1945 election with the largest vote swing in UK history. They passed the National Insurance Act 45, National Assistance Act 46, and the National Health Service Act in 1946. It might be worth taking on board the next few years. The sheer cost of paying for the healthcare of an entire country that had never free health before was staggering. I believe over half the country had dentures fitted because the nation's teeth was in such decay (not helping the stereotypes...) This led to the introduction of charges for dentistry, and later prescriptions. In the next election (1950), they only secured a majority of 5 seats. The following year, (in a lesson Theresa May might have heeded), Attlee called another election to secure a larger majority, in which the Conservatives then secured a narrow majority.
Hope you found this helpful!