I'm editing a generally well written, near-final draft of a biostatistics paper. Worth broadcasting are several writing problems that occur in almost all grad student writing. 

• Don't denigrate your contributions. 
  • Original: A simple way to achieve this ... 
  • Edit: A way to achieve this ...
  • Comment: Be respectful of your contributions. Are you so close to your own solution you can't see how important it is? Perhaps you've forgotten how innovative your solution was, given how long you've been living with it. Modesty, either real or false is not rewarded in academia. Besides, if you're really a scientist (and you are if you're a statistician), honesty is an important characteristic. Being honest about the importance of your work may not be easy, but it is important. Your work may be mathematically simple, but if you describe your idea as simple, readers will assume you meant that the idea is trivial.
• Don't represent,
  • Original:  ... [statement of key idea] because this represents [key idea alternative] ...
  • Edit: ... [key idea] because this is [key idea alternative] ...
  • Comment: Represents is wishy-washy and could imply any of a number of relationships. Be firm. If A and B are the same thing, say A is B, not A represents B. 
• Use the same language every time. ​
  • First Original: dispersion around $x$
  • Second Original: dispersion
  • ​Edit both times: dispersion around $x$ 
  • Comment: Apparently in the original text, there can be more than one dispersion.  Describing the dispersion as "around $x$", implies there are or could be other kinds of dispersions not around $x$. Thus the need to keep the modifier in repeated useage.  
• Plot don't Show
  • Original: Figure 2 shows ...
  • Edit: Figure 2 plots ...
  • Comment: Or: Figure 2 is ... . Figure 2 doesn't show anything if you're not well enough educated to understand the plot in the first place. Figure 2 contains the plot, but Figure 2 doesn't show anything.