My random tip is hit the gym, lose that belly, build up some He-Man shoulders like mine
. My XL shirts fit my upper body perfectly and is lose around my hips so I have zero
concerns of printing anything, even my full size M&P. No beer belly also allows me to instead of loosening up the belt one notch to allow for a IWB holster, keep it in the same notch to keep my gun super tight to my body - zero shifting.
Wear shirts made of heavy cotton/material.
Two shirts nearly eliminates any possible printing. White T with a button up works wonders.
Loose/large pants pockets if your carrying a pocket pistol. I check pants specifically for this before buying.
Try to avoid the normal "tells" of carrying concealed. Don't "guard" the side of your body your firearm is on, walk normal, get a good holster so you don't have to "check" it every ten minutes.
One of my random activities when shopping with the wifey is trying to spot people who might be carrying. If you know what to look for, you'll be surprised how many people carry. "If a guy is wearing a fanny pack and still keeps his wallet in his back pocket, there is a gun in his fanny pack".
Every guy behind the counter in a gun shop is carrying. Ask them for tips and tricks.