My rules, such as they are.
Rule 1: Do not skimp on carry gear. A belt that flexes and allows the gun to flop around will be uncomfortable, and amplify perceived weight, and it will also make the gun much more visible to others. A holster that collapses too easily may allow foreign objects to impact your trigger or safety... obviously not desirable. The ideal system keeps the gun tight to your body, minimizes its movement, and prevents inadvertent contacts with parts you don't want contacted.
Rule 2: Dress around your gun. It's entirely possible to conceal a full-size 1911. On some occasions, I've concealed a S&W 29 without much difficulty. T-shirts under structured outer shirts is my usual method, but there are any number of options.
Rule 2b: Recognize that there may be some circumstances where you will realistically have to make do with a much smaller gun. I can't hide a HiPower or 1911 when in shorts and a t-shirt or tank top; if I feel a need to be armed while participating in an activity where athletic clothing is the norm, then I carry a 442 in my pocket.
Rule 3: Don't fixate. Most people will not notice at all; if they do notice printing, most will assume cell phone, etc, not gun. Most people who do notice a holstered gun seem to assume off-duty or plain-clothes LEO. In other words, act normal.
Rule 4: Carry every day. If you do, it becomes much easier to behave in a normal manner when carrying.