This video gives a good guide on how to obtain 5 stars.
The tips that are talked about are constantly switching songs, to get the “heart bar” up; making sure to be on beat, and doing both requests at the same time, this will give you bonus points.
Another tip for starting out that I found helpful was to build your library with songs you can recongnize and you know the release date, genre, and title.
Hope this helps and if anyone has any other tips feel free to put them in the comments!