When it comes to wearing concealed carry attire, comfort and security are key. To ensure that your firearm is comfortable and secure, you need to choose the right type of clothing. Pants that don't fit too tight and a shirt that is long and spacious enough to cover the gun are essential. Formal button-down shirts are inherently tighter and less elastic than a t-shirt, so these may not be the best option for concealing your firearm.
Natural fabrics such as cotton, linen, and wool are ideal for concealing your firearm. A specific concealed carrying belt is also important for supporting the weight of the firearm and holster. Traditional hidden carrying belts are made of reinforced nylon straps, leather with a steel inner lining, or premium genuine leather. IWB holsters are probably the easiest holder to carry in a hidden way, since they're tall enough to hold and cover the firearm. When selecting a shirt for concealed carry, look for one with details that will benefit your lifestyle when worn in a hidden way.
A good pair of concealed carrying leggings should protect the trigger, support you without falling or causing your firearm to fall, allow easy removal and recast, and be comfortable. Women don't need to buy a completely new wardrobe when they start wearing hidden clothes; there are leggings, skirts, and other sports garments with built-in covers. When you decide to carry a firearm, choose whatever you're comfortable with. Any type of t-shirt can be made so that you can easily hide it without it being printed or the outline of the gun being seen through your clothes. A heavier frame can help compensate for a smaller charger and will not alter the concealment in most types of cases.
You don't necessarily need a belt made specifically for concealed carry; clips for beltless covers (UltiClip, Fabriclip, Discreet Carry Concepts) provide options for going without a belt. The base of a good concealed carrying shirt is one that hides your firearm, minimizes the impression and allows easy access. I have the Urban Carry holster; my firearm is so hidden that no one even knows that I have a gun.