Minimum list of "must have" features on a 1911 intended for serious use:
Sights you can see at speed. Not necessarily adjustable. I like a fiber optic front of .100 wide coupled with a rear notch of .125 wide. I dislike 3 dot, as they clutter up the sight picture. One dot on the front should suffice. An example of set of sights would be a Dawson Precision fiber optic coupled with a Heinie rear.
Extended Thumb safety. Not an ambi unless you're left handed. Ed Brown "tactical" is a good choice, as is a King's speed safety.
Beaver Tail Grip Safety. Ed Brown memory groove version. It not only does away with hammer bite and sharp edges, but drops the gun a little lower in the hand for better recoil control.
Crisp Trigger with overtravel stop. Around the 3.5# range would work for most. (this may already be present on the gun off the shelf) Length of trigger is a personal thing. They make short, medium, long, as well as custom lengths. Find the one that works for YOU.
Front Strap Texturing. This can be a 10 cent piece of skateboard tape or a full stippling or checkering treatment. It prevents the gun from twisting in your hand during rapid fire.
Beveled magwell or extended magwell. Not a "must have" but a strong "real nice to have" option. S&A magwells add 1/4" to the length, but make those fast reloads a lot easier. It doesn't mean you don't have to practice, tho !
Quality Magazines. Wilson's are fine, but I prefer the Chip McCormick Power Mags (not their cheaper ones with the welded floor plate) Either way, a crappy magazine is a mistake in any serious gun.
Quality Holster/belt You'd think it goes without saying, but buying a $500-$800 gun and then putting it in a $15 dollar Fobus or similar is just ignorant. Putting a good holster on the belt that came free with the pants is equally so.
The above list should serve you and your 1911 very well in many applications.
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