My take on concealment is that there are three elements, but I'll change one of them from what a poster above states.
The three main components are:
- The holster
- The belt
- The cover garment.
Let's look at each in turn.
1. The holster. This can be either Inside WaistBand (IWB) or Outside WaistBand (OWB). For the purpose of the this discussion we will not delve into specialty holsters, e.g. shoulder or Small-of-Back.
Buy quality, whether IWB or OWB, from a holster maker that offers concealment holsters. You can buy quality, but if the holster comes from a maker that specializes in hunting or competition, your ability to conceal adequately will be compromised. There are some board members who come highly recommended. My personal experience is almost exclusively Milt Sparks, but I recognize there are many, many other makers that fit the bill as well as Sparks does.
IWB generally speaking will print less than OWB in my experience. Some people report that they wear the same waist size when carrying IWB as they do without, others report that they buy pants and inch or two bigger to accommodate the IWB holster. I buy pants that are an inch larger than I need if not carrying IWB. Obviously if carrying OWB, then pant waist size is immaterial.
2. The belt. I cannot stress this enough... a quality GUN belt will help immeasurably. If you decide to carry IWB, you can scrimp or compromise slightly insofar as the concealment factor is concerned but make no mistake, the comfort factor will not be as satisfactory without using a dedicated gun belt. A&G is my recommendation as well. I have a Don Hume and a Milt Sparks but the A&G is superior to either.
If you elect to carry OWB, the belt is even more important than the holster. It must be rigid enough in the vertical plane to support the weight of the holster and the gun and keep it snugged in against your body. A less rigid belt will allow the butt to sag or be pushed outward, making a larger bulge. Comfort will also be affected.
Lastly on the belt, make sure the belt size matches the loops on the holster. Do NOT use a 1 1/4" belt for a holster that has 1 1/2" loops.
3. Cover garment. Must be loose enough to drape around the gun. I wear 1X without a gun, 2X with. It must be long enough to hang below the visible portions of the holster. Again fairly obviously, you can get by with a shorter length shirt when carrying IWB than you can when carrying OWB. Be aware of how high it will ride up when you reach up for something. You don't want the bottom 2 or 3 inches of the holster being exposed when you grab that can of beans off the top shelf. Dark colors are better than light colors. Patterns are better than solids. Heavier material won't drape or snag on the butt as easily as lighter materials. Square cut looks neater than shirt tails meant to be tucked.
The laws in your state will tell you how much you have to worry about an inadvertent flash of your weapon. As I understand it, in Texas, for example, ANY view of ANY part of your concealed weapon can lead to legal repercussions. Here in Indiana, the LCH is good for both open and concealed carry so even if your gun were to be fully exposed, there is no law against it. After 10 years of carrying, I don't worry too much about a quick flash that may show my gun anymore. I was paranoid about it for the first six months or so.
Oh, fwiw, I'm 5'7" and 240. I carry a full-size 1911, a compact 1911, or a S&W 442 as the mood strikes me. The 1911s get carried both IWB and OWB. I almost always have a single or double mag carrier on the off-side as well. The Smith is either pocket carry or IWB in a FIST clip-on.
My favorite cover garments are chamois shirts in the cooler months and cheap Sam's Club washable silk "camp"/"Hawaiian" shirts in the warmer months.
Last comment: people don't notice you as mentioned above. I dropped my compact 1911 out of shoulder holster onto the floor in the middle of a crowded video store one Friday night years ago. There were probably 20 to 25 people around me. So far as I could tell, not ONE of them noticed what I dropped and bent down to retrieve. A little bulge in your shirt at 3:00 will NOT be noticed by 99.5% of the people you meet.