Pay close attention when the others have said to buy a good belt. This is advice worth heeding. The sky is the limit depending on your budget, but the best I have found for high function at low cost is the Wilderness Instructor belt. Get the 5-stitch model, no need for the stiffening insert unless you're carrying a full game rig with lots and lots of reloads.
Carry behind the point of your hip. It's not perfect, but there is no perfect way to carry a two pound piece of steel attached to your waist. Behind the point of your hip (3:30 position) is the best of all possible imperfect ways to carry a handgun. Any other position should be viewed as a situation specific compromise.
Carry a reload. Not only because magazines are the foremost cause of malfunctions, but because of your comfort. Even one reload helps balance the load on your hips. I carry two when i can conceal it, for this reason. The odds of actually needing two reloads is infinitely small. Comfort, however, is a daily thing.
Be honest about your wardrobe. Not everything in your closet will enable you to conceal a handgun. Not everything will enable you to conceal with a particular holster. I prefer OWB carry, but carry IWB when cover garments will not allow the slightly more comfortable OWB holster. A full length mirror is helpful. A second set of eyes even more so, until you get the feel of concealing well.
Be aware of how you move. Certain movements will alter the fit of your clothing, as well as the position of your handgun relative to your body. It's called "printing". It means someone can see the outline of your pistol, usually the grip frame, through your clothing.
Speaking of printing, shirts with patterns, especially darker colors, work very well to conceal a handgun. The darker the color of the shirt, the less important a pattern becomes. The lighter the color of the shirt, the more important the pattern is. It draws the eye away from a specific point (your gun) and tells the eye to "Oh look! A pattern! Let's try to see it all at once!"
Depending on your shape and the fit of your pants, consider the inexpensive Perry Suspenders. I think they are made by Dicky. Elastic, but strong enough to spread the load across both your waist and shoulders. I tried them once several years ago and now wear them daily.