“Good writing should be convincing because you got the right answer, not because you are good at arguing.” – I think a lot of people stand behind their arguments thinking that if they say something the right way, they will win. But one well thought out point can and usually will outweigh many random smaller points.
“In an essay you don’t take a position and defend it… you notice a door is ajar.” – With an argument, if you have it before writing, it is most likely to have already been argued. Though it might be more common, people will feel less obliged to read it’s points and ideas because they have probably already been seen.
“In a real essay, you are writing for yourself, you are thinking out loud.” – I think this is especially important to keep in mind. Because everyone has a voice, when we write, we actually are voicing our thoughts. A lot of time, if our paper is an argument, we will not be there to back it up so it is important that we do our best in writing it.
“An essay you publish ought to tell the reader something he did not know.” – No one wants to read ‘common knowledge.’ If readers have heard it before, why should they hear it again? If you are stating something that is interesting
“If you want to write essays, you need two ingredients: a few topics you’ve thought about a lot, and some ability to ferret out the unexpected.” – Expecting the unexpected is always something we should do, especially while writing. Because you do not know about how things will pan out, it is important to go into writing with an open head.