Well, to be honest, the first thing I see is a lot of notes. Then, because I am curious as to what it is called and I know where the title is I check that out and perhaps the name of the composer.
I like the other answers to this as well. The question itself it too broad. Perhaps a better question would be when you open to a new page of music, what should you look at before trying to work on it? The best few first steps would be the title - it gives you a feel for what to expect-, then check out the clefs, key signature and time signature and any general directions at the beginning so that you don't end up playing a song you did not mean to. A smart musician would then look thru the entire piece trying to get a sense of the flow and patterns, any surprises or changes, check out the rhythms looking for tricky spots and decide how you will handle them. Then check out the notes. Are there any notes way out there? What sort of moves will be required to play them? Anything weird and unusual? Are there patterns you already know like 5 finger patterns, scales, broken chords, that might make trickier sections easier. You should also look for any changing directions so that you don't have a nasty surprise you have to stop and fix.