Once people pass that difficult mental threshold of "possession-equates-to-competence," and realize that they would benefit from some formal, professional firearms training, the difficult task of selecting good instruction begins. Being somewhat of a connoisseur of firearms training, here is my $.02 on the matter:
CURRENT/FORMER MILITARY INSTRUCTORS:
It is true, over the past 200 years the U.S. military has been the premier firearms training school and has turned out generations of excellent shooters, but having received some military firearms training myself during my years as a competitive shooter, and having spent ample time on the firing line with military shooters, my take on pretty much all military training is that it doesn't really teach new skills as much as help someone bring to the surface skills that they already have deep down inside, usually by repeated applications of something called "suck." While this is certainly effective for training a large captive audience with varied backgrounds and varied levels of experience with firearms, it is not always useful for the majority of civilian shooters who are paying for more gentile, sophisticated firearms training for concealed carry or home defense. Also, not everyone in the military was Carlos Hathcock or Dick Marcinko.
Someone in the military did laundry, someone in the military cooked dinner, someone in the military drove trucks... not everyone in uniform is a Delta/SEAL/Ranger/Green Beret/Operator/etc... and even if they were, a lot of folks who carry guns for a living view firearms the same way carpenters views saws and hammers; just tools for the job. A lot of them really aren't gun guys and unless someone was a designated marksman or sniper, current military doctrine favors the "volume of fire" approach that typically isn't appropriate in a civilized shooting where a little more discretion is necessary. In case you have any doubts, consider that some statistics indicate that U.S. Soldiers expend an average 250,000 rounds of small arms ammunition for every insurgent killed in Iraq and Afghanistan, up from a reported 30,000 rounds per enemy K.I.A. in Vietnam. During the first gulf war, more 40mm grenade launcher ammunition was fired than standard 7.62 machine gun ammo. When the States allow belt-fed 40mm's for concealed carry or home defense, I will change my tune on this, but until then, my verdict on military background instructors is that the select few of them that actually have really useful stuff they could teach, usually won't teach it because they think it's some dark, secret "tradecraft" that us "lowly civilians" don't have any "need" for...whatever. I'm not saying that all instructors with a military background are bad, some are absolutely the best, I'm just saying that a military background is no guarantee of a competent shooter or a competent instructor.
LAW ENFORCEMENT INSTRUCTORS:
"...but my instructor is a SWAT cop" Same logic applies, the Police Academy has produced many, many, many fine marksmen. I know cops who are excellent shots and very skilled firearms handlers... some of those are also great at passing those skills on to students in the form of instruction...
...but by and large, most cops are not gun enthusiasts and shoot their firearms only twice a year at qualification day when they are expected to exhibit only the most rudimentary firearms handling skills. Now... don't let this dissuade you from getting training from law-enforcement background instructors if and when you can, they are generally more willing to share their knowledge and what they have to share is usually more useful to a John Q. Public in concealed carry mode than military-style training. Just make sure they are the real deal and not some mall ninja looking to pick up a fan club and weekend beer money by telling war stories (that probably happened to someone else) for 12-hours and calling it "instruction."
CIVILIAN AND NRA INSTRUCTORS:
Over 200 years of civilian shooting activity in this country has probably added more to the art and science of firearms handling and marksmanship than can be measured. The dedicated competition shooters in IPSC, IDPA, Bullseye, 3-Gun, Highpower/long range rifle, Silhouette and of course all of the various hunting disciplines are the truest practitioners of the craft and have formed the basis of the majority of law-enforcement and military shooting programs, or contributed to them heavily. Some of these guys really know their stuff, but just as the 2 categories above, there are some that you shouldn't listen to under any circumstances. I probably should apologize in advance to some of my fellow NRA instructors, present company excluded and all that, but as I didn't apologize for my criticism of some Law Enforcement and Military "trainers," here goes:
You probably know as well as I do that some people who gain NRA instructor certification should find different hobbies because they give the rest of us a really bad name. If, as an instructor, you can not pass the qualification requirements that you expect of your students, my personal opinion is that you should hang it up and get more practice and some advanced training until you can hit the target consistently at the required distances in the required time... as a good start.
So... how do you identify and chose a competent instructor? I just said having a certificate from the NRA or a background in law enforcement or the military doesn't necessarily mean anything. My advice is to consider those things baseline qualifications when looking at an instructor, they should have at least one or more of those qualifications. Once that is established, you should consider the following:
#1 Don't be afraid to judge the book by its cover. An instructor should dress and carry themselves in a professional manner. A sloppy appearance, poor linguistic skills, or speaking abusively and rudely should be your first clue to look elsewhere. That said, don't be scared off by instructors with a few tattoos, for example, you're not looking for sewing lessons after all. I know some excellent instructors with a very clean-cut look and some who have a more "extreme" look. One thing they all have in common is the ability to look people in the eyes and effectively communicate.
#2 Are they insured? Professional instructors carry insurance for the same reason people have fire-extinguishers in their homes. Just having it is the first step to never needing it. It indicates they care about the student enough to spend a lot of money on something they will probably never need.
#3 Do they practice what they preach? What do you expect to learn by taking a concealed carry class from someone who never carries a concealed handgun?
#4 Who is training the trainers? Where did the instructor receive their training and how long ago was it? Have they taken any additional training since then? Some people are adamant that an instructor has to have "experience," to have "seen the elephant" or "been there done that." That's like suggesting you shouldn't take driving lessons from someone unless they've been in a car wreck. While that may give the participant a unique perspective, such things affect everyone differently and their experience may have nothing to do with the experience that is waiting for you tonight, or next week or next year. The fact that someone has been in a firefight doesn't necessarily mean they learned anything from it or that their performance was all that great. Satisfactory results can reinforce bad tactics. Who wants to take defensive lessons from George Zimmerman? Why not? He successfully used a firearm to defend his own life... Actually, we can all take a lesson from Mr. Zimmerman... don't be "that guy."
Regardless of "experience," the best instructors continue to study and comparing notes with other instructors, taking additional classes and seem to have an attitude of "Always a student, sometimes a teacher."
#5 Do they know their tools? Don't take a concealed carry class from anyone who carries any type of handgun in a Fobus holster. Here are some things make me suspicious of a lack of competence right away: 1. Cheap holsters, 2. Primary concealed carry handgun in a caliber less than 9mm *if semi auto or less than .38 special for revolvers. 3. "Gimmicks" like unconventional modes of carry or macho handguns like the Taurus Judge or Desert Eagle Magnums.
#6 Techniques that don't work for everyone not built like Arnold Schwarzenegger. Since most of us are "average," I want techniques and skills that are adaptable to "average" people.
#7 Reputation: Ask around, ask for references, most especially talk to former students.
#8 Legitimacy: Don't even consider taking a class from someone who cuts corners on required time or range requirements. Applying for your concealed handgun license with credentials from a class you know didn't meet the requirements can get you in trouble with the law, and maybe in bigger trouble if you actually do find yourself threatened.
#9 Safety: If they don't run a safety-first operation, move along, nothing to see here. Keep in mind, just because a practices looks "unsafe" to you, doesn't mean it is. Some folks aren't comfortable training on a "hot range," for example, but many instructors do it every day with no negative effects. When it comes to safety, look at track record and if they're scrupulously following the 4 rules of firearms safety.
#10 Cost: usually you get what you pay for. A $50 concealed carry class may punch the ticket legally, but isn't likely to be a quality training experience.
Those are my basic recommendations. Here in Ohio (if you're not training with us, or need a type of training that we don't deliver) I highly recommend Tactical Defense Institute in West, Union, Ohio. There are other schools around the country that have great instructors such as Tactical Response and Thunder Ranch. There are a few travelling trainers hosted by organizations such as Buckeye Firearms that are top notch as well. Attending some of these can be a very expensive proposition by the time you figure in travel, accommodations and ammunition, but see #10 above.