There is an ongoing debate among actors as to whether it is better to start with externals and move to internals, or vice versa.
It doesn’t really matter where you start, as long as you approach the internal aspect in an “organic” way. Whatever triggers that for you is fine, if it works.
Years ago, Paul Muni and Laurence Olivier were among the best actors of their generations, and both began with externals. “What sort of nose does my character have?” Truthfully, they fall a bit short as actors by current standards. Their approach seems like artifice to today’s audience.
Meryl Streep has received criticism throughout her career for paying meticulous attention to hair color, accent, etc., the implication being that it is all about externals for her. The thing which keeps some people from feeling warm and fuzzy about her is probably more a function of the characters she has played than her approach as an actress. In addition, Streep’s chameleon nature is under a microscope in film in a way that it wouldn’t be on stage.
You can develop an honest performance by starting with externals. Joanne Woodward has acknowledged that she starts with what her character looks like, what sort of hat she wears. Woodward is entirely believable in her roles and won a well-deserved Academy Award for The Three Faces of Eve, so she has used this approach to great success.
Probably more actors start with internals than externals, but there is NOTHING WRONG with feeling that you start with externals, as long as you do it properly and dig a good foundation as well.
In fact, I think you’ll find that anyone who starts with externals and does it well is also pursuing the internals simultaneously. He just starts paying attention to externals earlier than some other actors do.
Which brings us to the matter of impersonation, which is not the same thing as acting.
For people who make a living as an impersonator, like Frank Caliendo and Rich Little, capturing the unique identifying characteristics, tics, and vocal peculiarities of well-known personalities and casting them in a humorous light is much more important than creating a completely believable character. They are comedians, not actors. Believable isn’t the point for them; recognizably accurate is.
Any time you play a real, historical person on stage, particularly people we’ve seen and heard on video or film, you risk becoming an impersonator rather than an actor. It is easy to be so concerned about being faithful to their external nature that you forget to do the extra work required to find the inner person who manifests those externals.
It’s not easy – playing real people on stage is very challenging, just as talking directly to the audience is. Combine those two things in a one-person show, and you’ve got your work cut out for you. Line readings become a very strong temptation in this situation. After all, it’s unnatural to speak to people who never talk back, who don’t respond “in character”, because they aren’t characters, they are audience.
One-person shows are a peculiar combination of acting and stand-up work, especially the comic portions of the show. Only the best actors can pull them off in a way that makes the audience entirely suspend disbelief, because “staying in the moment” during them is so damned hard. Without that, we simply make a tacit agreement to be entertained as opposed to moved. We accept the mimic and laugh at the humor inherent in the lines. In other words, we laugh at the jokes, not at the character and his situation. It’s more about entertaining than it is acting.
When you choose to play a stereotype, you risk impersonation. All right, no one “chooses” to play a stereotype, but that doesn’t mean that it isn’t something we can end up with without realizing it. Stereotypes are always based on externals and generalized adjectives. There is some bit of truth behind them, or they wouldn’t be stereotypes. However, if you don’t discover what makes this individual’s stereotypical qualities unique, you won’t be an actor; you’ll be an impersonator.
I don’t think I’ve yet explained the difference between “over-actors” and “under-actors” (we all are one or the other; learning to act is about finding the balance between the two). But I think “over-actors” are more susceptible to mimicking and the line readings that can result, because they are more concerned with “entertaining” the audience than “under-actors” are.
[I am framing this piece with Youtube video links to two of my favorite one-character plays about famous people, with actors who make it look easy: The Belle of Amherst, with the incomparable Julie Harris, who was nominated for more Tony Awards (ten) and won more (five) than any other performer; and Mark Twain Tonight, which Hal Holbrook has been performing for 47 years. Both actors won Tonys for their performances in the original Broadway productions (Holbrook has had three Broadway runs of the show.) The link to Mark Twain Tonight is just a promotional piece, as the full video from the 1967 television production isn’t the best quality, but you can find it on Youtube as well.]