Silicon is used to lower the viscosity of the weld puddle. This allows better flow of the molten weld puddle.

Dross

Partially by the smoke that is produced. This helps to keep the surrounding air away from the puddle. Mostly by the slag that covers the weld almost immediately as the arc moves on.

motion of the electrode causes different pattterns in th formation ofthe cooling weld puddle. You can alter the weld patter by changing the electrode motion,,ex: motion straight across the weld zone and dropping electrode position say (1/8th inch) produces given pattern..same pattern with a slight upward motion at edges of weld zone another pattern...etc etc

watch your puddle advance at a rate that will allow the puddle to still be spreading as you advance . set .045 wire at about 26 volts and wire speed at about 275 you also have to have the proper weld angle. so in reality the only way is practice practice practice