Proof-reading
It can be very frustrating proof-reading your own work, not least of which because it is very difficult to spot your own errors. However, one of the key generic skills that you acquire as a doctoral graduate is a professional level of writing; that title, Dr X, means that from now on you will be entitled to have opinions on other people's writing and they will expect that you have got it right.
Here's a recent examiner who was less than happy with the quality of the writing and he explains why: bad writing gets in the way of good ideas! (The emphasis is that of the examiner.)
"Overall I was very disappointed with the very large number of punctuation, spelling and grammatical errors through out the document (well in excess of 100). They badly detract from the reading of the thesis as one spends one's time looking for the errors, rather than focussing on the content of the research. This thesis does not appear to have been adequately proof read. This is very disappointing where clearly a large amount of work has gone into preparing the thesis. I would strongly recommend that if the candidate hasn't got the time to do this for themselves then they have a professional proof reader do this for them. I have listed a very large number of the more obvious errors, but I am certain that there are many more within the document."