Moss in your turf can be caused by an excess of shade, nutrients and compacted soil. A soil test is a good place to start to understand some of what is needed to increase the health of your lawn. Here is a link for the UMN area that accepts and analyzes soil. https://soiltest.cfans.umn.edu/ Once you have test results back you can begin to amend to provide the appropriate nutrients. If your soil is compacted you may also have to aerate as a method to loosen it. Spring is a good time to do this. Excess shade can support moss growth. If this is the case you can either eliminate the cause of the shade or plant grasses, such as fescues, that better tolerate lessor light. 

Below are two additional links with informaiton to assist in supporting a healthier lawn. 

Moss in Lawns
https://extension.illinois.edu/lawns/managing-moss-lawns
Lawn Care Calendar
https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar