In Infamous the hardest thing to look for are the blast shards. All the game gives you to look for them is a L3 press people call a "Ping" While most people go around randomly 'pinging' the map, the smartest thing to do is go around block by block. The best thing to do is go around the perimeter (The docks and piers.) and keep pinging in tell you circle the entire island. Once you do that go to city blocks and go around each building while pinging, then, Go around the block pinging, and finally once you have all the blocks pinged get on the nearest railroad and ping your butt off tell you circle the rails. Repeat this process in the other islands tell you have all 350 shards.

Above is a map of the shards in the Neon. ( Found on Bing.) Couldn't find one for Warren or Historic.