A short one:
Drop the “I” in “As I mentioned earlier.”
Just write: “As mentioned…”
(Two further notes: Do not overuse this phrase. Also, see if you can drop the “earlier” – the past tense tells us not to fast-forward.)
The rest of the tips are available at: http://www2.arnes.si/~bjason/LW%20tips.pdf
(Skupno 6 obiskov, današnjih obiskov 1)