First off I'd like to say this trophy is a pain in the ass
Now that's over here's my guide for the trophy. In Infamous you have to collect these blue shards scattered over the game's map and there is a total of 350 of these (do not get confused with the inclusion of blast shards obtained from missions because they won't matter in getting the trophy faster or not.
A couple of great sources to use for getting the shards and keeping track is: http://www.ps3trophies.org/forum/infamous/13789-blast-shards...
The first link is good for copying into paint and then crossing out each shard needed and the second is good for any tricky ones to get (which most are easy to find as they are out in plain sight minus a couple, but the ign link works really well.
I also highly recommend keeping track of your number of shards collected by doing them one island at a time, making it easier for you if you happen to accidentally avoid one.
There are 147 shards in the Neon District (however one of which will not be able to get to with out returning from the second area)
a total of 135 in the Warren District
and 68 in the Historic District (the last one)
Note that the last two districts only unlock after completing a majority of the story and, blast shards do not appear on your map until you pick up an unmissable shard proceeding through the third story mission.
Have fun going for this very boring trophy!
PS there is no way to tell where any shards are so its up to you to mark them down