What method did painters use to achieve a realistic style?

It looks like you posted this twice, so here is my answer from your other post:

Artists used and use linear perspective to create a realistic style. Linear perspective is when an artist bases shapes, figures, etc on their relation to the horizon. The ultimate effect of this is that it allows an artist to create depth (3D feeling) on a 2D piece of paper

the decreasing neutrality of the u. s. in world war i

hope this : )

answer placeholder because the system is messed up