If there are spirits around that need help, they tend to gravitate to those who can help them, so I'm sure you will find them.

I do this work often, but be aware that once you start doing it and they know you do, they tend to 'follow' you home looking for help, so if you go to places where people are likely to have died, like hospitals, old age home or cemetaries, check to see if any followed you looking for help.