Voice acting at it's core is acting. Acting in it's simplest form is you making choices towards something you want.
Want is the key ingredient of acting. Without a want or purpose, your cooking has no flavor. It's digestible, but not likely something you'd eat again - or acting terms, not something you'd believe.
It's not as hard as it sounds. Everything you do in real life is a result of something you want (or need). You wake up in the morning because you want to go to work. You work because you want money. You make money because you want to pay rent and buy food. Etc, etc.
Even doing absolutely nothing is a result of you wanting to do nothing.
So in any voice acting performance, always find and know your want. As a beginner, start there. It will give what you say meaning. As you advance, you'll add the additional layers of personality and traits to fully create your character.
Remember when you were a kid playing pretend? You believed you were an astronaut, or doctor, or superhero. A kid might not know all the nuances and have the mature knowledge to be any of those realistically, but I'll be damned if you can convince a kid they're not actually one when they're playing.
As many people grow up, they also grow out of things. They can lose the innocence and fun of being a kid. People become self-aware as teens through to adulthood, and hold back on actions where they might feel judged by others. The word "childish" gets a negative connotation, but in acting, it can be your best friend.
With acting, you have to let it all go. The moment you have hesitation, the performance is no longer believable.
Look at all the pro VAs, they don't hold back. They go 100% in their performances in both voice and body (sometimes adding incredible physicality like Mark Hamill).
It's also important to be yourself. You are unique. There's only one of you. And the choices you make can only be made by you, based on your life experiences. So bring yourself to the performance. It's what makes you stand out from the thousands of other actors.
It's fine to learn by imitating other actors, but you'll rarely ever get hired by acting like someone else (unless you voice match a celebrity or audition for Mickey Mouse or Bugs Bunny).
Richard Horvitz describes it best in a way that makes the challenge of acting less intimidating (and it's in his teaching style) - don't think of it as voice acting to scripts, but as you playing pretend in stories.
~ Foxwolf
I mention this on the Improv 101 page, but this show is a gem. The YouTube clips are vignettes, a look behind the curtain of these celebrity actors, being their true selves, giving advice and sharing the challenges they faced on the journey towards their acting career.
For full episodes, catch on offcamera.com or Netflix.
Alan Tudyk
Strip everything and keep it simple - what does your character want? Don't think about the finish line. Just keep running and focus where your foot is going to land next.
Adam Scott
It's okay to do things that suck. Just like making mistakes. You learn not to do them again. So keep trying, keeping sucking until it gets to something that works.
Jenna Fischer
People new to acting can sometimes have a self-doubt and lack of confidence in the art of performing. Know that you matter just as much as anyone else, and that it's not about arrogance, but confidence, and that you're allowed to be yourself.
Willem Dafoe
All actors are terrified. As adults, we're conditioned not to play and be loose. Get rid of the baggage and embrace the unknown.
Jake Gyllenhall
Pick up little pieces of experience in acting training and life and put them in your endless bag of acting tools. Always keep the bag with you , so that when a moment comes in a performance, you can take that something out immediately and use it.
Don Cheadle
Being an actor doesn't necessarily mean having an acting job. You can act anytime. Read plays, work on monologues, do script analysis, read scenes with other people, audition, perform in local productions. That's all part of the work an actor does.
Also, in analyzing scripts, understand what's going on, why characters are saying certain things - what's the text? What's the subtext? Make sure you know what acting is. Once you do, more than half the work is done. Then you just play.
Will Ferrell
Understanding that acting takes both hard work AND luck sets the reality in that becoming successful is extremely difficult. Knowing it's like winning the lottery, it should take the nerves and pressure off of you to just go for it And if you make it, you made it from being you, and not because you tried so hard to be something else.
Jeff Daniels
There's a difference between knowing the script versus knowing what to do with the script in terms of acting choices. Do the work. Drill the script. Once you know it, you can dance around with the words rather than worry about remembering, familiarizing or understanding it.
Matt Damon
Work harder than everyone else. And knowing that the system isn't design for newcomers to succeed, sometimes you have to do all the grueling work on your own to get a chance at breaking through the wall.