I think the hardest part about carrying a firearm for the first time is:
1) Figuring out where to carry that best suits your body shape/build
2) Getting comfortable carrying a round in the chamber with no safety.
3) Knowing how to move with a firearm on your person.
4) NOT telling all your friends/family that you carry. I personally don't think any one needs to know but yourself.
5) Knowing how to tell if your gun is going to expose itself without using your hands to feel/touch. You don't need to feel/touch your weapon every minute.
There are a lot of people who get new garments for their "carry system." I did not, I figured out what would work with what I had. I was not going to go out and buy a new wardrobe to carry my daily carry weapon. While some people have the extra money to buy 7 pairs of new jeans/pants, with a mix of shorts -- good for them I didn't. Also, some people like to buy 5 or more pairs of 5.11 brand tactical pants, at a rate of 70+/- dollars per pair, that is just too expensive. ( I did buy a holster & gun belt for my system )
I am a short fatty, at 5'7" 170 lbs, I wear fitted clothing. Everyone can see I have a gut, I look better with fitted cloths -- I wear Large American Apparel T's, they are a skinnier cut T and to be honest aren't very long. My usual daily wear are: Jeans with T or Shorts with T. I do have blazers/sport coats with dress slacks, I usually go to my LCP for this setup.
I carry a SR9C in the 5:00 - 6:00 position, using a Crossbreed Supertuck Holster with Crossbreed belt. My wife says when I move around a lot she can see that there is something there but if she had no idea I carried she wouldn't know what it was.
I often do NOT wear any type of jacket, just jeans/shorts and a T.
There are some situations that I have to be careful, if for some reason I need to bend over to get something off a low shelf in a grocery store, I don't bend over -- 99% of the time the firearm will not be exposed, but it will print. There are some states out there that printing is a big NO-NO. So I have learned to drop to one knee to get something from a low shelf.
Also, if I am going to sit down to have lunch at a restaurant, or sit down in general, I grab the sides of my pants, and make sure they are a little higher than they should be, then I pull down my shirt as well; so when I go to sit down, the firearm doesn't have a chance to expose it self. When I go to sit up I do the same thing in reverse, make sure my shirt is down then when I stand up and make sure my pants are high up -- a few steps later my pants re position themselves to a perfect height again.
There are a lot of people who seem to spend every moment of their life trying to tell if someone is carrying, most of these people are other CCW permit/license holders and feel that if they can spot someone they believe to have a weapon, every bad guy can as well. They are the ones that ridicule those of us that do carry for not being tactical enough. Now I am not saying all of them are mall ninjas, but some hold that mightier than thou sentiment.
Also, making sure you know how to draw your firearm well: clearing the holster, pointing your gun forward to the target, coming up with your pistol to align the sites, pressing the trigger, ready position, scanning for targets, aim, press, then re holstering your pistol in the same manner that you draw is a big thing. You need to practice your draw, also re holstering your weapon is just as important as drawing your weapon. A lot of people get sloppy when they re-holster-- this is not a good habit to get into, you want to re-holster in the exact reverse of the way you draw
If you don't already have a good gun belt I would suggest getting one, I thought I had a good thick leather belt, then when I received my gun belt... lets just say its a world of difference.
You will figure out what works best for you, you just have to try things, everything.