In today's technology-heavy world, when you say you want to work in IT, that can encompass thousands of different IT jobs and disciplines. Most employers in IT want specific skills, and matching those skills with military experience can be difficult.
There are essentially two different paths that you can take, and which one you choose is based largely on how soon you need a job, what skills you already have, and what your mid-term goals are.
The first path is something that I'll call "broad focus". That is, you want to work in IT, but you don't have a large amount of focused training experience in a specific IT discipline. Generally, if you want to break into IT on this path, you would probably be starting out in an IT Helpdesk job, which isn't necessarily a bad thing. An IT Helpdesk job is where a lot of us started out, and requires minimal specialized training or certification. Once you have a foot in the door, you can then use the time at that job to learn a more specialized skill to move within the same company or a different one. For this path, a general IT certificate like a CompTIA A+ certificate may give you a leg-up.
The second path is something that I'll call "targeted focus". If you still have time until your exit from the military, you could spend more time up front learning and getting certification(s), and try to jump into something related to that skill. For example, you can tailor your training/certification to the areas of PC repair, networking, security, databases, collaboration (email, etc.), identify management, or just about anything else. Certifications are good, but for some jobs are increasingly becoming less important. To learn more about what may be required or reasonable for the job you want, seek out and ask those who work in that field. This is where it helps to join communities/groups such as those on sites like LinkedIn.
In my case, I took the first path. I started as the helpdesk person for a local school. A year later, I moved up to the district office as an "IT Generalist". I spent nine years learning many different IT disciplines, but found that I enjoyed endpoint (PC) management the most. (Warning... the pay at school districts isn't good, and your opportunity for advancement tops out quickly if you don't have a teaching certificate... but the jobs are relatively easy to get).
After nine years, I decided to join the "real" business world. (I should have done this a few years earlier). I targeted "endpoint management" (patching, OS deployment, and imaging of Windows PCs) since that was I found I enjoyed the most. Within a few months, the perfect opportunity came along in a location that I wanted to move to, so I made the jump to "Corporate America".
Interestingly, in the IT world, you have to have a bit of luck. Short contract work, mergers, acquisitions and outsourcing are very common. For example, I got my first "corporate" job at one company (about 50,000 users) doing endpoint management. That company was acquired by another company a couple of years later. A few years after that, the second company outsourced their IT to a third company. Fortunately, I had that bit of luck and got to ride from company 1 to 2 to 3. Same job... different name at the top of my paycheck. IT jobs also have a tendency to be outsourced to workers in other countries.
If you want to maximize your stability (raising a family, etc.), you would want to avoid job postings that list a contract term and look for more permanent "on staff" positions. Contract work is common in IT. Many companies without large IT departments hire third parties to do major changes/projects. Those third parties hire people to support that specific project. Larger IT service providers keep pools of talent that may move around to support different clients (physically or virtually). So... try to find the positions that have no contract term.
Additionally, many companies are splitting their IT jobs into US-based and non-US-based divisions to save labor costs. However, there are often data restrictions that require that certain data be accessible by only U.S. citizens. One such restriction is for "ITAR" data and systems (International Traffic in Arms Regulations), but there are others. One way to gain some job security is to seek out training and become certified to handle this data since these jobs cannot be outsourced to overseas locations.
One tip: I've sat on several hiring boards, and most have done some additional research on the candidates beyond their resume. We've looked at Facebook pages, blog posts, LinkedIn profiles, and any other information that could be found easily on the internet. When preparing for an interview, make sure that your internet presence gives the impression that you want it to. Time to purge those old pictures of drunken parties and funny cat videos.
None of this should dissuade you from working in IT. Information Technology can be a very rewarding and exciting field! I hope that some of this helps you direct your efforts. I wish you great success at finding your path outside the military.
Overall, be flexible, get your foot in the door, learn on the job, and discover what you really enjoy and run with it.
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