There are a number of things that you can do to update your skill set and reestablish your professional marketability. I don’t know your specific technical specialty, so I’ll try to make my suggestions applicable to technical jobs in general.
Do your research
Your first step is to gain an understanding of what exactly has changed in your technical area. If your specialty is related to using a software package, then find out what has changed architecturally and functionally within the software package. Alternatively, if you are in the datacom side of the house, identify what new hardware devices have entered the market and what enhancements have been made to existing hardware and its related software.
Pick your battles
With your research complete, divide the technology changes you found into two primary categories; first, technologies you really want to dig into and learn, and second, technologies you just want to be cognizant of so you can speak intelligently about them during an interview. After all, you can’t become an expert in everything. Note that when choosing which technologies you truly want to learn, consider the accessibility you will have when trying to learn the technology.
Find access to selected technology
In many cases, the hardest part of studying a technology is gaining access to it in a way that it can be studied. That said, if your selected technology is free to attain or inexpensive to purchase you’re all set and off to the races. If, however, this is not the case, here are few tips on how to gain this access:
If your technology is software based, call the vendor, explain your situation, and ask if you can have access to a cloud-based test region of their software.
Call your old employer, explain that you are trying to update your skills and ask to work on the technology free for a month or two. The company will get free labor. You will get professional-level experience with the technology and recent work experience, thus illustrating your reentrance to the work force. Also, who knows, after some volunteer work your old employer may offer you a job.
Find a local non-profit organization using the technology, explain your situation, and offer to work there part time free until you find a paying job. In return, you want flexible hours so you can interview as needed, the ability to work your selected technology, and a professional reference if they think you did good work. Also, as an additional benefit, you are helping the world by providing value to a local charity.
Formulate a study plan
Once you have access to your technology, create a detailed list of all the things you would like to learn. Note that, in addition to learning the new features, this is also your opportunity to learn things about the technology that existed prior to three years ago but you never had the need/occasion to use. Lastly, having not used the technology for three years or so it may be worthwhile to also spend a little time refreshing your previously known skills.
Find free stuff
When not working hands-on on the technology, look for free sources of study materials. It’s amazing these days what you can find on the internet. There may be free white papers, YouTube videos, blogs, discussion boards, and other valuable information right at your fingertips waiting to be accessed. Note that these free internet-based information sources can also help you gain a general understanding of the technologies you wanted to be cognizant of but were not selected as your primary area of study.
Now that you are spending all this time reacquainting and expanding your knowledge in a specific area, target your job search toward opportunities using that technology. After all, not only are you in the process of retooling your skills in that area, but you also have a great story to tell prospective employers about your retooling process. It shows your commitment to your profession, your ability to formulate and execute a plan, your self-starting nature, and your willingness to work hard toward a specific goal.
In closing, good luck and best wishes in your job search and career development.