Ive been carrying a full sized hand gun daily, for 40 some odd years now. Its not at all difficult if youre willing to do it.
A good belt and holster are key to pulling it off. Ive always found IWB holsters to work best, and these days, Im really diggin on AIWB. Its way better, and for a number of reasons.
You need to watch any gear that sits below the bottom of your belt. Holsters, pouches, etc can quickly give you away, if youre not paying attention.
You also need to get over the need to adjust or "check" your gun (good gear helps eliminate this). You also need to understand what behavior needs to be adjusted, like how you move relative to how you carry. Certain methods, locations require different ways to do things.
Your attitude is as, if not more important than your dress. If you act guilty, or sketchy, people will believe you. Just act normal, and go about your business, and most wont give you a second look. Making eye contact is normal, and also keeps others eyes focused away from what you dont want them to look at. Avoiding it, makes you look like youre up to something. Lighten up! People are much more responsive in a positive manner, if youre friendly, even if its just to say "hey" and smile.
Another thing to consider is the shape youre in. Ive carried fat and skinny, and skinny is definitely easier, and gives you more options. Being in shape also helps big time with your shooting.
As far as dressing around the gun, a lot of that will depend on what you normally wear, and do.
You may want to start adjusting your wardrobe to deal with things now. Sudden changes tend to be noticed and even questioned.
Fleece's, sweatshirts, untucked shirts, etc, are going to be your friends. If you need to wear tucked in shirts, then that tends to narrow your choices, but these days youre in luck, there are a bunch of options that werent available not all that long ago.
This time of year, you want to layer, gun or not. Its the proper way to dress for the cold, and it allows you to remove one or two things, and still have a cover layer. One heavy coat basically sucks for the cold and for carrying a gun.
Dressing appropriately for the season or environment is a necessity too. Out of place clothing, tends to be noticeable, and again, even questioned. Its not hard to adapt, but you do need to be aware.
Watch things like spare mag carriers, and even holster choices sometimes. If you use a knife sheath, multi tool carrier, etc, someone might just ask to borrow it.
Theres lots to think about, but its really not tht big a deal, if youre sensible about things.
another thing to consider, is pay more attention to everyone, and see if you can spot the other guy carrying. Lots to be learned there.