"Practise, practise, practise." You'll hear those words echoed across your life from every teacher, mentor, tutor and parent who care about your talents and how you express them. Without practice, talent is nothing. But how does one practise acting? What we mean by that is, how do you get better at acting when you're on your own. Actors can find it difficult to know if they are improving, as they often can't know if what they are doing is right, without an audience of some sort to react. And what is 'right'?
Out of all the arts, I don't think we have much of a shared language to judge performance, which is freeing and frustrating at the time. Watch your favourite film actors and try to describe why their acting is better than others. I'd suggest you'd follow Alice down the rabbit hole on that one.
So what can we do?
An actor's mind can feel like a juggling machine: Stand here, walk there, hit your queue, hit your mark, know your lines, diction, accent, sight lines, listen to the other characters, react, ....now this time with FEELING. As an actor we are always yearning for that moment, whether on stage or screen, where we fly. And suddenly we're not ourselves and are completely in the moment. I would argue that if we have worked on our technique, on all the technical aspects we have to juggle to the point they are subconscious, then we can "play". When we play, the audience are with us because they cannot predict us, and that is exciting to watch.
Here are a couple of practical things you can do to allow you the space to do what you really want to do: act.
Always warm up, particularly if you have a tendency to clench your jaw. This can be as little as a couple of minutes, tongue and lip stretching, yawning, humming (use M, N and NG noises) and massaging your facial muscles. Many actors use a bone prop https://vimeo.com/30619101 or even as Kathleen Turner did, half of an old cork. Find yourself a list of tongue twisters to practice and a piece of text to work on over time. If you have a noticeable weakness, like a sibilant S or weak T then use pieces of text that heavily uses these sounds.
People learn accents very differently and some people seem to take to it better than others. However this is definitely an area where practice really helps. There are many books and DVDs that can help, as well as the Dialect Archive: http://dialectsarchive.com/
At home it can be as simple as mimicking characters from tv shows to give you a feel for how an accent might feel in your mouth. If you aren't comfortable with accents then I'd choose a couple that are particularly useful and work on them. As most of our TV is based in the South East of England I'd suggest learning RP, Estuary English as somewhere to start. If you already have one of those accents, look at what your casting might be and find something that fits that. TV particularly can work with broad strokes in casting (a nice way of saying stereotypes) so keep that in mind. However if there's an accent that you just like...learn it and have fun doing it. Everyone seems to enjoy a Southern Drawl.
Too many actors wait for the phone to ring. Even those who get jobs straight out of drama school or get lucky with a few jobs in a row need to remember that every actor goes through a time with no jobs and no idea why. So keep finding ways to act. Do staged readings in someone's front room. Join monologue slams. Make short films with your smart phone. Write and perform your own sketches. Find like-minded people and make your own work. Join classes and workshops. There is so much we can do to keep acting and keep developing our skills.