The most difficult thing about cycling with pedestrians is a lack of predictability. I use a bell from a long distance off but try not to use it close up as a last resort yelling works but isn't pleasant.
A typical scenario is the walker turns looking over one shoulder but turns around the axis of their head (understandable) and in order to do that they take steps around in a circle crossing the path you can't tell if they will go CW or CCW so the person warned late really needs the space of 3 walkers to avoid them.
Another is that, without any attempt to look or determine the direction of the warning bell they just step left or right. This even occurs randomly if they are already at the edge of a path - they are just as likely to step into the middle as the side.
Groups are even worse - unless one person hears before the others and coordinates the group, people turn, step side ways, cross the path in seemingly random directions.
Phones and headphones significantly add to the problem and massively disrupt situation awareness (especially for riders when headphones seem like madness to me).
Dogs and dog walkers range from the sane and pleasant to the barking mad and dogs are as thick as shit and seemingly lack any sense of self preservation relying on their owners for instruction (which they frequently don't get). They should be a law against extendible leads with black cable!
Most of this is quite normal and quite understandable and there are a couple of generally useful principles that are useful in dealing with this:
(1) The faster or more mechanical you are the more you should take care not to injure others.
(2) Mixing peds and bikes is much kinder on everyone than mixing cars and bikes (or cars and peds).
(3) Be nice to your fellow person - try not to run them down, startle them of knock them off their bikes.
Warn early and take care - it's not too hard.