Reply by rag3

Quoted from randa

[...] I prefer demo/medic calling

Any combo IMO will work as long as its a heavy class. Quoted from Ritalin

[...] What is this micro-management you speak of? Main calling is something I'm really trying to improve, so I'm looking for all the tips I can get. My team is very vocal and sometimes it works very well, but sometimes it's difficult to make organised calls.

At lower-levels, you have to micro the positioning of the player. During pushes, you might have to do massive calling and try to put every class in a position. Its like playing starcraft 2. :P haha. Uber takes the Macro attribute.