Sight picture and trigger squeeze. It doesn't matter if it's a .22 or more, the sight picture and trigger suqeeze are the keys. FWIW, I shoot thousands of rounds of .22 by choice instead of the center fires. Among the less obvious reasons are: You don't have to concern yourself in chasing brass-a huge distraction from shooting, the smaller holes made by a .22 are less of a distraction when shooting at a dark target-less chance to look *beyond* the front sight and admire your handiwork(or lack of) during shooting,Less noise-I find I can get by using ear plugs rather than muffs w/.22's-far less fatigue during long sessions.
As far as pistol vs revolver goes-A new revolver is going to set you back plenty, somewhere around $350.00 to $450.00 for a good D/A. Ruger offers their SP101 D/A in .22 lr, but they are hard to find. Most decent pistols are half that amount. Top choices for inexpensive yet outstandingly accurate are , Ruger 22/45, Browning Buckmark Camper-in the $190.00 to $230.00 range. The Buckmark standard and Micro add another $30.00 to $50.00 to that price, along with the Ruger Mark II line, for the $230.00 to $300.00 range. A .22 conversion unit for the 1911, Glock and Beretta can be had from J.A. Ciener-
www.22lrconversions.com for $200.00 to $250.00, depending on which model. The main difference is in the sights. Another possibility is a CZ 75B in .40SW or .9mm with the Kadet .22 lr conversion unit. Any of the above will offer decent sights, good out of box trigger-as good as most stock centerfires- and accuracy that is better than 99% of anyone can shoot.
FWIW, my favorite of the bunch is the 22/45. It's inexpensive, impossible to wear out, has the same sight picture as my Browning Hi Power, and is accurate enough to put a scare into empty 12 ga shells at 50 yards on one of my good days. Second would be the Buckmark Camper. The Camper is a basic Buckmark, with a rougher finish and a bull barrel. It is well worth the savings over the standard model for a knock about type of gun, yet still has the same comfortable grip of the standard model.
That touches briefly on the handguns, in a rifle, just about anything you can get in a centerfire, you can get in a rimfire. My personal favorites are the Winchester Lever and te Marlin Model 60 in an auto. If you don't care for a tube fed, then Ruger offers a magazine fed auto, as well as a lever action. Remington also has a good auto in the 597 line, but it looks a little *chunky* for my tastes, YMMV. The autos and the bolt actions can give outstanding accuracy out to 100 yards, while the Lever actions are less accruate but a lot of fun nonetheless.
Don't delude yourself, shooting a .22 is more of a challange that you might think. Putting tiny holes close together is a lot harder than putting big holes close together. One of the strangest things I've run across on theinternet is a sport called "Bottle Cap Shoots", where .22's are used at 100 yards. the winner is the one to hit the greast number of milk bottle sized targets, closets to the center. The difference between 1st and last place is measured in tens of thousandsth of an inch!
Have fun, .22's are great. Everyone should own a bunch of them.