As others noted, selecting clothing to fit around the gun is critical, as is a good quality belt. My favorite belts are the Beltman cowhide belts, which I have in the 1 1/4 inch width in black and brown. I like the 3/4 inch hole spacing. The precision of the fit is as critical as the rigidity of the belt for good comfort and good concealment.
If I expect to sweat, and am using a closed front concealment garment, I will use a Wilderness Frequent Flyer or a Maxpedition Liger. I added extra holes to the pre-existing holes of the Liger, giving me 1/2 inch hole spacing. Use a heavy duty punch for this - the material is so strong that I completely destroyed the punch I used in the process.
I saw ankle holsters mentioned. They are a poor choice for getting into and out of vehicles - which you will likely do in places where it would be best that the gun remain hidden. Even the best ones are uncomfortable all day, every day. My current favorite is the Galco Ankle Lite or Ankle Glove. C. Rusty Sherrick also makes a good ankle holster.
What has worked for me is a Kydex IWB holster carried at about 3:30 on the belt. You have numerous good options. It will hide under a jacket, untucked polo shirt, sweater, etc. For summer business casual carry, I use an Aholster pocket holster.
If you do use a shoulder holster, use one with a figure-8 harness and spare magazine pouch on the off side. This will keep the pressure of the back of your neck. Adjust the shoulder straps tightly enough so that gun doesn't flop around, but not so tight that they pull the gun outward. This avoids the need for belt tie downs, which tend to pull the gun in weird ways as you move.