1st Person Perspective Pet Peeves
First, the word "I" should start as few sentences as possible.
Second, I try to avoid using phrases like "I noticed", because they say the obvious. Let's look at the phrase "I noticed a girl looking at me." Well duh, that's obvious because if the character didn't notice, they wouldn't be writing about it. It would have been much more to the point and more like showing as opposed to telling if one wrote "A girl was looking at me." See, doesn't that phrase sound better? I suppose that it could work in some rare cases, but this is one of those "99% of the time" things.
Those things were in the back of my head, and I felt like putting it out there.