First of all a lot of your questions can be and have been answered in some of BOS resources which you can access
here.
Women had to take up work to help with the war effort this lead to them earning money and having employment for many of them the first time.
Propaganda helped to gain support and influence people to take action and do their bit to help the country.
US entry was considered the turning point as at the time morale of the allies was down and the war wasn't going well. The US entry meant not only fresh troops but a huge and much needed moral boost.