What are the best types of smaller concealed carry firearms, and what is the most comfortable way to carry it?

Define smaller?
That means two shot .380 to some, and a "small" 4" 1911 to others.

For me it means striker fired sub 3" 9mm or .45 or .40
Glock 26 Gen 3 (9MM) The Glock 26 was designed for concealed carry. ...
Springfield XDs .45. ...
Smith & Wesson M&P 40C. ...
Beretta Nano. ...
Springfield XDM Compact .40S&W
Smith & Wesson M&P Shield .40S&W
sig p290

as for carry,
good belt is required... a good gun belt, not something from your local big box store.
Im using armor belts right now. https://www.armourbelts.com

for holsters, 90% time im in a outside the waist band carried at 3:30 strong side, 10 deg froward cant.
D.M. Ballard http://dmbullardleather.com is what im using currently but holsters are like chips, you cant have just one....as well as., the best you know is the best you have used... until you buy, try and use another one, you will never know if it is better or not.

for the 10% i am not in a OWB holster, i carry in a cross breed super tuck http://www.crossbreedholsters.com/Product/SuperTuck-Deluxe

I have all the guns listed above except the Glock....and they all have more than one holster.....the daily carry is a xd .45 thats been tuned...and personalized..id have to count... but be surprised if i had less than 6 holsters for it.

I use a holster by Sneaky Pete as I didn't want to change out my wardrobe. I carry a Sig P320 Compact in about the largest one they make. I love it. Just like carrying in a old .45 flap holster. Lest you think it is slow on the draw, I got where I could draw, chamber and engage in 2 seconds w the .45. This is as fast as it is striker fired and already chambered. Check it out.

SFC Jim Ruether that is akin to asking what is the best car, motorcycle, beer, soda, or pizza. Ask one hundred people, get one hundred different answers. I personally have a Kimber micro .380 (which I am going to trade up for the 9mm) that I enjoy shooting. I also have a Walther PPK in .22 that I use really just for the range. As for holster, that is another that is going to vary with the individual. I agree with MSgt George Cater that the Sneaky Pete holster is a good choice as it hides in plain site. As long as you have a belt, you have a concealed weapon. I carry my firearm in a pocket holster.