How to create a high quality icon for my Windows application?

Question

If you are running Windows with a higher DPI setting you will notice that most application icons on the desktop look terrible. Even some high profile application icons such as G

Answer 1

I converted my .ico to a .png and then back to an ico on this site, and it seems to have worked: http://convertico.com/

Looks like it added 48x48 and 64x64.