I am aware of needing to find the right voices from the start, Hannah, but it's less like a worry and more like a strong awareness. It doesn't stop me from writing, but as a story develops and I'm still not finding distinctive voices, I gradually become more aware of it. Maybe, if I get a novel to the point of having finished a proper first draft (which is where I've nearly got to with the one I'm working on), I will find it easier to sort out voices as part of the redrafting process.

Emma, I have a list of notes along those lines which I think I probably got from you some time ago. I do look at them, when I'm starting to develop characters, but I rarely get further than just looking. Again, maybe I will find it easier to go through all of those things if I ever get a story properly to the point where I know what the story is and am looking to refine it.

I think it might just be a problem with finding variations on English accents/speech mannerisms, as it seems to be less of a problem when a character speaks English as a second language. I find it much easier to imagine, say, a French or a Russian accent, than several different English regional accents.

I've now written two books in the first person and the big danger is telling and not showing. This happens because you are unable to tap into multi points of view so the temptation is to try and fill in the background detail with a lot of information rather than take the characters aside and show it happening in real time with dialogue.

For example you might want to give the reader some important background into perhaps how the main protagonist met one of the other main characters in the past. Rather than describe how it happened it is much neater to rewind the clock and show their actual first encounter, what the protagonists first impressions were etc etc.

There is also the possibility of using multiple first person points of view but I've never been able to master this and it made the manuscript messy and disjointed but I'm sure there are many many better writers than me on here that can do this with ease.

Hope this helps...

There is also the possibility of using multiple first person points of view
 

I've read two novels where there were 2 first-person points of view used. The first was Mothernight, by Sarah Stovell (who used to be on here - is she still?). The other was Allegiant, which is the third of the Divergent trilogy. In Mothernight, it worked really well, as the two voices were divided up neatly so that you could see who was saying what. In Allegiant, it jarred a little, possibly because the first two books in the trilogy stick strictly to a single POV. So I think it can be done, if handled well, but it requires careful handling, and possibly even more careful planning to work out whether it's right for the story.

Yes, I think alternating first-person narratives (n.b. technically, "first person" isn't a point of view) can work very well, but only if you can make the narrative voices very distinct. That's what anchors the readers in that character's personality and consciousness, so that the reader never unconsciously or conciously comes to and thinks "Hang on, who is this?".

FWIW, I have two in The Mathematics of Love (relatively easy because they were 150 years apart, so the voices were naturally very different), and three in A Secret Alchemy. That was harder because two of the voices were brother and sister. But in the event I needn't have worried: their personalities were so different, and their narratives differently constructed, so it was fine.

On things becoming too Tell-y, I think it's true. On the other hand, if you can find a strong narrative voice for that character, and a powerful reason for them to be telling their story, then the Telling itself becomes a kind of Showing, because how and why this character is telling their story comes over so strongly.