Here are a few things to think about as you go on your journey from disarmed citizen to armed self-protector.
The first step is to determine if you are legally qualified to carry a gun. If you are a legal citizen of the United States and can answer questions 11.a. through 12 on ATF Form 4473 appropriately, and have the funds, you can buy the firearm of your choice from a federally licensed firearms dealer; or in some circumstances, another private party.
After making sure that you are legally qualified, the next step is to check the laws in your state of residence. While there are federal firearms laws that apply in all 50 states, each state also has its own patchwork quilt of firearms laws. The best resource for checking on your state and local laws is the NRA website. State government websites will often have a page detailing that state's laws related to firearms purchase and concealed carry.
The states of Alaska, Arizona, Kansas, Maine, Montana, Wyoming and West Virginia allow for any legally qualified gun owner to carry concealed handguns without a permit (so-called "constitutional carry"). There are laws and restrictions on where you may carry in these states, so it is your responsibility to study the laws of your state to understand them as they apply to you.
The remaining forty-two states have some sort of "Shall Issue" or "May Issue" laws regarding concealed carry permits. Put simply, "Shall Issue" means the state will issue a license or permit to any person who meets certain criteria, usually legal qualification and some form of training. "May Issue" states add a further restriction by requiring the applicant to "prove" they need a handgun for self-defense.
The second step is to select a handgun for concealed carry. There is no "one-size-fits-all" answer here, because everybody is different — different sizes, body shapes, clothing choices, hand sizes, comfort with various calibers and platforms, and other factors. A larger framed man may feel perfectly comfortable carrying a full-size .45 caliber 1911 pistol inside the waistband. A smaller framed woman may prefer a .380 Glock in her purse. The potential concealed carry holder should shoot several different guns before deciding on one for carrying purposes.
Next, whether your state requires it or not, taking a concealed carry training course is a great idea. During this class you will review the legal ramifications of concealed carry, discuss tactical considerations and in many states will participate in a live-fire exercise. Many instructors who teach these classes also offer additional advanced classes for even more skill building.
Once you have completed your class, you will go to your appropriate state agency to apply for the permit (in my home state of Ohio, for example, county sheriffs are the issuing authority). You will be fingerprinted and a background check will be performed. It could take a period of days or weeks to finally get your permit, but once you do, you are legally sanctioned to become an armed defender.
The last step in the process is to determine what you will do in a defensive shooting scenario, including what you will say when you call 911. Being involved in a defensive shooting is not something most of us anticipate, and having made the decision to carry a firearm, it is something we all must be prepared for.