I am trying to edit a short story, written in the first person. I have used "I" way too many times, it stands out too much at the beginning of a sentence, but I can't seen to change it without losing the meaning/tone of the sentence.
A technical term for this is "filtering," meaning you're often reminding the reader what POV (or filter) rather than leveraging the context of the situation to make the filter implied and unwritten.
Instead you want write from "inside the character's head," tight enough that you're inside his body.
Ex of filtering: I found the envelope in the supermarket. I reached past the butternut squash and I grasped it, and I pulled. I noticed the envelope smelled like crayons fresh from the box. I twisted the envelope and whatever was inside was stiff and unbending. (Lots of "I" filtering, explicitly written at the front of many sentences.)
Ex of less filtering: The envelope came from the supermarket, hidden among the butternut squash. After pulling it out and examining it, the smell of crayons fresh from the box teased me to discover more. Cautious twisting indicated the contents as stiff and unbending. (Who's doing the activities is implied.)
Lance's example is excellent. It may also help to vary sentence structure (you may already be doing this). I'll give an example that retains the "I" but improves variation.
From I ran from the minotaur, and he chased me down the darkened, stone hallway. I grasped for my sword only to remember I had dropped it running from the goblins the day before. If only I had saved my flying potion, I could get out of this dungeon alive!
To The minotaur ran towards me, so I fled down the darkened, stone hallway. Grasping for my sword, I sadly recalled that it was lost during yesterday's flight from the goblins. The flying potion that I had needlessly consumed was what I really needed, but without it, escape seemed impossible.