I'm 1800ish USCF. I don't feel qualified to be a coach. I can certainly share tips and ideas, but I don't think I know near enough to be a coach. I'm sure an 1800 rated player could help a 1000 rated player, but the 1800 players need help too 
Sometimes it seems that the better I get at chess, the more I realize that there is a lot I don't know about chess.
The student, or the student's parents, determine what your strength should be. I live in "Silicon Valley" and here there are a lot of Indian and Chinese families who are willing to pay to have their childern coached in chess. After a few years, they usually discover that "skill at chess" has nothing to do with "skill at live" and they stop paying for chess lessons.
i disagree chess motivates you to look behind the things. i think it would be weird that you dont have more skills in life with chess.. all other hobbies nowadays seem to just mkae the mind lazy, but maybe thats just my opinion.
It think we should have 2700 annotated what people above 2000 know " not in terms of playing strenght but in terms of ideas and chess knowledge!"
that would be cool and if they would tell who qualifies as a good knowledgeable coach and who doesnt