Getting Training Isn't as Easy as It Used to Be
It used to be common for companies to train people on the job. These days, it seems that companies want to hire someone who can hit the ground running. I guess that leaves the training up to you. I believe that anyone with an interest can learn retouching with Photoshop, as long as the desire is there. Many schools have Photoshop night courses, and those may be an inexpensive option. You know yourself well enough to know how you best learn.
What Kind of Background Do You Need?
I do feel that the best retouchers are people who have an artistic background. I say this because you have to be able to imagine the look of an image before you even retouch it, such as where a shadow falls and how it interacts with the rest of the image. Whether you model with clay or sketch cartoons, I don't think it really matters as long as you have the artistic sensibility. As long as you know what you want to achieve, the rest will fall into place. I think you should have good listening and communication skills as well. Being able to interpret what people tell you and convey your ideas and thoughts are important.
There are many retouching opportunities out there. The only downside I see is that many, many people want to get into it. It is like computer animation. It seems cool to do. When retouching started, it was limited to high-end proprietary systems that were very, very expensive. The time charged out for retouching was also very expensive because there was really nowhere else to get the retouching done. These days, anyone with a few hundred dollars can pick up a computer and Photoshop, and they are in business. Also, many people fresh out of school with few responsibilities can afford to work for less. Many ad agencies know this, and people starting out in ad agencies will work there just to build up a name for themselves, gain some work experience, and develop a portfolio. Not a bad idea if you can afford to do it.
I find that many people just starting out do not have a pre-press, print, or color background and do not fully understand the correct way to prepare image files for various print media. Many images that come to me have to be readjusted to suit the needs of the print application. Of course, experience can be gained, but it is like anything else it takes time to develop.
Gaining Experience and Building a Portfolio
As I mentioned, working for someone else is a good way to develop a portfolio and build some credibility. When you work in the industry, you will also develop some contacts, and your name can get around if you're good (actually, it gets around if you're bad, too).
You could contact some beginner photographers and see if you can work with them on projects, as their work may not be as high end and the projects may be a little more laid back to work on.
Sources for retouching employment include ad agencies, design houses, and companies that have in-house art departments. Companies with in-house art departments seem to be a growing trend, as they can keep everything under one roof. This may include photography, scanning (dying off) design, and retouching to final files that are ready for print.
If push comes to shove, you could approach photographers and ad agencies and ask them if you could redo a job that has been done before just to show them what you can do. The only problem you may run into is that most of the images these people have are client images, and they may be reluctant to hand them out. You could go and get some stock photography sources like iStockPhoto (www.istockphoto.com), download some images, and retouch them.
The problem with doing work for many agencies and photographers is that the ad deadlines are very, very tight. Many times jobs are wanted the next day or sooner. It's tough for them to rely on someone they don't know to do their retouching. Again, I think your best option is to redo work if they'll let you and keep track of the time you spend doing the retouching. That way, you can give the potential clients correct timing for jobs.
You could also do what my father used to do. Being an ad man, he used to look through magazines, find lousy looking ads, and redo them the way he thought they should look. He used to get many accounts by impressing them with what he had done or had redone.
So now, let's get on to the hands-on business of retouching with Photoshop.