Post the first line from your last 25 fanfics and try to find a pattern. ( ...well, I went with the first sentence. )Hmmm, patterns. Obviously, not beginning with full sentences;) (Well, 5 out 25 are not but they do stand out.) Only three start with speech (and one of those is an actual quote from the movie), and quite a few are in first person.
Three start with a name, four with 'I' (8 with pronouns), 7 had just about enough info to guess the fandom. Three mention a place.
Surprisingly, only two start with waking up. (Three if you count the one that infers waking up, more if you count metaphorical waking ups.)
I am surprised that half seem to be in present tense. I honestly thought most would in past tense. Shows what I know...;) I also use ellipses a lot.
One pattern to all? I obviously try to begin with something that would keep me reading. Straight to the point, no waxing lyrical on the place or endless descriptions.