as far as i know
gOOD SOP will be the one
1.Written by urself not copied
2.be true with ur ideas and aims
3.Try to write according to the standard of ur education bcz if u'll use some very difficult vocabulary every one can think that u have copied or its not written by u
4.Be concise and focus on the main points
5.SOP must length just on 1 side of paper and must show that dream of ur passion relates to ur homeland