08/28/2013 08:07 PMYou spam one key as fast as you can the following way:
Posted by kiza
That may be the easiest way, but it's not the best. You want to cast as many DSs and EBs as possible, but you never want to cast frost nova more than once per second. If you spam all 3 spells, you have to choose either to get as many EB and DS casts as possible while sacrificing WW casts by over-spamming FN, or cast the correct amount of WW but have fewer EB and DS casts by slowing the spam.
There are several ways you can accomplish the ideal EB+DS spam and FN casting. You could use some sort of macro (works well, but technically against ToS if you are the equitable type), you can do it all manually (honors the ToS, but is very difficult/painful), or you can hold some keys down similar to what kiza linked (feels a bit weird to me, might take some getting used to if you normally do something else).
You can hold EB and DS, then spam WW, and hit FN only when you want it to go off. You can put either WW or FN on left mouse, so if you would rather spam WW with the keyboard, that works too.