I knew a pastor in Seattle, he's still there I bet, that carries. He wears slacks and a tucked button up shirt and carried a full size 1911. You couldn't tell. I went to see him a few times, and I knew but couldn't see it.
I can give you a few tips. I use a Milt Sparks VM2, and it hides a G27 or 29 superbly well. I bet it works even better with thinner pistols, I hear it does. It is the only holster I use for CC'ing an auto now, and I own (soon) three; for me it is the best carry holster in the world for so many reasons. The holster and the belt are at least as important for CC as the weapon is, and the belt I have is a heavy double thick belt, soft but it won't fold. You'll need a good dress style one though. Milt Sparks makes good belts, but I've seen those Galco dress belts and they look good but I don't know how they wear. Bladetech will make one for you with plastic inside and I bet that is a good way to get a dress belt that is stiff. Whatever you get, the goal is to have a stiff belt that doesn't fold that pulls the (quality) holster in close to the body. Without that as a minimum, you can't hide credit card.
I generally wear 5.11 pants (I just found they are real comfortable and pretty tough and for what I do they are fine) and an Underarmor or similar type t shirt and a fleece. Or an open Tommy Bahama shirt over the undershirt in the summer. Looser fitting pants enough to accomodate the holster work best, the underarmor shirt is just comfortable, and the fleece is thick enough to hide anything. In the summer, the Tommy shirt is made of heavy silk and drapes well plus the patterns break up any printing. This works the best in my experience.
For dress clothes, I actually had told the tailor to cut it around the weapon and I wore the rig to the tailor. He also reinforced that area. So I have a tailored black suit that hides a G27 or a G29 in those VM2's without any problem at all. Pretty awesome. I suppose you could get a vest for under the jacket and that would work as well as long as you told the tailor and wore it to the fitting.
For no jacket, the VM2's have kydex clips. The first one I got came with them a long time ago, then when everything went up, Milt Sparks kept the prices down by just charging for those. So I have the one set of clips and can say they work well if you need to tuck a shirt in. Here I bet the prints or patterns of some kind would still be best, and getting it cut long and maybe a size or so over would be best.
Carry is all about compromise. In general, looser fitting clothes hide better, but may not look as sharp. So going to a tailor for dressier clothes is kind of a must in my mind, or it isn't really worth wearing the dressier clothes. The above works well for me and I'd always have my wife and my friend check me over when concealment really mattered, and that G27 is the smallest pistol I carry.
I also have a 340PD that I keep for pocket carry worth mentioning. I very, very seldom do this, but it is light enough that nobody would spot it for a weapon even if they saw a bulge. In a good holster, it is also small and light enough that it would hide VERY well with dress clothes. Because dress clothes are usually so light and the belt is thinner, it makes hiding a heavier pistol harder since it pulls down the belt line. That 340PD and those other scandium frame revolvers won't have that problem. The G29 for example is much harder to conceal with lighter dress clothes than the G27 is.