Concealed carrying of a gun depends on two factors: clothing, meaning proper selection; the skill to carry a gun and equipment (the lack of a special holster in most cases can be compensated for by the selection of clothing). I suggest
check out this store, something you can choose here. For summer, choose a T-shirt close to body and wear a loose shirt on top (a size or two larger). It`s easier in winter, but when picking out a jacket, try to avoid those models that have inside patch pockets on both sides. So when pulling a gun out you might get caught by the trigger or bolt in the thin but tough fabric.