LPT: When peer editing a paper, read it through one time like you hate it, and a second time like you love it

Be the most hypocritical person you can be the first time. Mark every error, even if it's minor.

The second time, mark everything that you love about the paper. Mark all the good wording and things that you liked.

It may seem rude to make so many markings, but it will really help the writer.