The first option is to look for some private certification or training program. These types of programs are available far and wide can be done in classrooms or correspondence and will usually target many of the specific skills that you'll be interested in.
The problem with these types of programs is that they rarely fall under any higher authority and as a result, the quality of private programs can vary wildly. Some are excellent and will teach you all you need to know while others may fall short of your expectations. If you choose to pursue this option invest a lot of time researching the program you're interested in. Find out what others had to say about the program and how employers regard the program.
The next option is to take a two-year technical training program. These programs take a more formal approach to education, having classes all day long. Some higher body will normally oversee this kind of program, guaranteeing certain minimum levels of quality. This means that you can confidently enroll in such a program knowing that they will teach what is outlined in their curriculum with a reasonable amount of competency. In this case, make sure their course outlines match what you want to learn.
Two-year programs of this type will normally have some entrance requirements based on your performance in high school and that may consider work experience if you've been out of high school for some time. The private programs we discussed earlier won't have any such requirements.