Little things mean a lot. They can make the difference between a good and bad day.
On the way to work this morning, one of my shoelaces was loose. Since I'd run out the door at the last minute and trains don't wait if you're late, I didn't have time to tie it. So, all the way to the station, I kept thinking of how loose my one shoe was.
Waiting at a restaurant to be seated. That's another thing that's irritating. If there's more than a fifteen or twenty minute wait, we usually leave.
Someone bumping into me on the street and not apologizing. Someone honking a horn too loud, even if not at me - another little thing.
A lot of these little things add up to a miserable day.
Same thing with a manuscript. Watch out for the little things. Make sure you put your commas in where you should. Check your spacing. Check for those little words like a, an, the. Did you forget to insert one? Use an easy to read font, one that the editor you submit to likes.
There are many other little things to watch out for in a manuscript. Try to catch them all or you'll get a rejection letter which means a lot.