Training/ Classes
So you've got this great, check it out! This page will give you some idea on where and how to look for any formal training or classes that will benefit you and your needs as an actor.
A couple of things: As I said before you need to know what type of work or medium you want to focus on. as a theatre trained actor and director and professor of theatre at a university. I will always say theatre training is going to always benefit you the most for it's indepth work, but, there are classes and studios that focus on camera acting and auditioning for the camera only. Thing is with theatre training you can easily do both with just film training you will have a more difficult time accomplishing your needs as an actor in a live theatre production and I always tell students to not limit themselves.
Classes/ Studios
So, again to the point. If you are in a major city check your websites and search out studios or private acting coaches that may be of assistance. There is usually someone everywhere teaching acting or camera work. They just can't usually afford, marketing like most larger businesses. So, not hard to find. If you are in a rural or smaller area, you will probably need to leave town or move anyway to allow yourself more work opportunities. Also, most states in the country have at least one or two professional regional, summer stock, or community theatres that can and do offer classes, so you can check with them. This can be a good option especially if it is a professional theatre because it may lead you to eventually get on their stage, hence building block to the ol' resume. Some of the most amazing actors I have worked with in theatre grew up working or training in community theatre. The great thing is that it allows you to build experience, you remember that "picking up the raquet" thing. So if you are older (and by that I mean established, have a job and family) seeking individual classes and private training is the better ticket rather than dropping everything and attending a training program or college. They are demanding and require lots of your time in order for you to benefit.
University and Professional traning
For some theatre schools in the country that are connected to a university or dwell within one, the focus is very elite and very professional. Some schools promise professional work and/or union (or equity) membership after or by graduation. Some hold full scale professional showcases that are attended by agents and producers for casting and or hiring and these can be just undergraduate programs. These are usually programs that also end with the student having a BFA. Some are so elite that students must be evaluated in order to maintain enrollment. What you will usually find is most universities have a theatre or drama program, but they are either more taylored towards a BS or BA in theatre or Drama, which is more on the education of theatre and students in these programs usually attend for a basis into a graduate program or to go into the world of theatre as an educator. Trust me there are some phenomenal BA programs out theatre, but the other BFA ia a program that normally gears students into the training of being a professional artist. To clarify, the BFA is more recommended for the student pursuing work in profesisonal theatre and the BA, seems to have a more general and focused background that limits certain training and is meant for a student that wants to focus on teaching or going up to a graduate program.
I know many students who are professional actors now that just have a BA, but if you are starting out I recommend a BFA program that can be more specialized to acting or what have you.
MFA or graduate work:
Next, some students seek out MFA programs if they feel they need it or if they have only a BA or other. MFA programs have grown tremendously over the years for all areas of theatre. They are very strict programs that focus only on your discipline (acting, design, directing etc.) Most will connect you to professional work or prepare you with a body of work that will have you the most prepared for the work world. These programs are very competitive for example: acting programs usually take only 6 to 8 actors every two years or 2 directors and other year etc. They pay your tuition, you usually have an assistantship (teaching or working) and you are busy 12 to 16 hours a day. So this is why they can be competetive. These programs usually crank out the most professional artists in the business. Side note they only accept those that are certain they want to be professionals, not teach.
Experience
One other way actors have trained themselves is through "doing" and being around the work or others who are trained. The way apprentices did it in the time of Shakespeare. Find a local community or professional theatre and volunteer or if you are lucky, get in an internship. Start auditioning for community theatre shows and do, do, do, do. You will get your break and time on stage will grow and develop. You will learn if you take your work seriously. You will probably find yourself seeking out material on the craft or classes.
Experience is everything in acting. I have hired many actors based on experiences with several different theatres, than an MFA with only the experience as a lead in every production in graduate school and no outside experience
At the end of the day. Casting directors want you to be good and like all businesses they want you to be someone they want to work with, so it is important to get the working experience as much as possible to develop work ethic in the theatre or film industry because it may be the person next to you in one job that gets you the next job.
So training is vital. You may get a job by luck or a fluke with zero training whatsoever, but that job will be over then someone is going to want to see to act. So weight it out and see what works