Acting can be seen a little like learning a second language. From a practice standpoint.
In the beginning, you know a few words and have a few tools at your disposal. As you get better you can go deeper into a language, and maybe even get a few jokes, and carry on a conversation. Go even deeper, and you will get the "inside jokes" of a language, things like playing of words and such. When you become turely fluent, you're not even thinking of what you're going to say. You have a thought and communicate it.
Acting is very very similar. At first, you do everything with just the few tools that you have. You're really good at angry, so everything takes on that color. After a while, you get a little better, and have some measure of proficiency, and can call on different emotions. Go even deeper, and you see what the writer meant or the deeper meaning in the script and how it all ties together. But when you're really fluent, when you've reached the point of virtuosity, you find that you're just communicating. You're not thinking of what to say next. You're feeling, and the words just flow out.
This all happens, of course, through practice.
It's amazing, really, that people would never think of going to a foreign country without even picking up a phrase book. Yet they would get up on stage and try to give it a go. Even better when the director, or casting looks at you like, "What was that?" and you go into a explanation of what you were trying to do!
You need daily practice, just like you do in a foreign language. Sure, if you live on set, and you're on day 106 of a 200 day shoot, I would think that you have your stuff pretty well dialed in. This is like living in France for a year, and really having your french dialed in. If, however, it's been a while since you've had a audition, and you're current scene partner is lame about making it to rehearsals, Wwell, you're probably going to get a little rusty. Just like if you came to the states and didn't speak a lick of French for a while.
If you met a French person, you could get your point across, but after parting ways, you'll probably be thinking, "Ah, I should've said it this way, not that way." Does that phrase sound familiar? Ever had that internal dialogue inside your head after an audition?
Yeah, thought so.
You need to practice every day. You need to be emoting. You need to get your tongue around some words. You need to be moving. There are a lot of ways to make all that happen. Stay tuned, and we'll give you some tools.