Shoot as many different 1911's as you can ...at least in 4" and 5" barrels...and some with alloy frames and some in all steel - and some in 9mm as well as .45 acp...
Figure out the features you like - and want - and want to pay for. Things like having the front strap and back strap on the gun checkered ( at the lower end of the price range - guns like some of the Colts are not checkered), night sights, a Mag Well or speed chute, ambi safeties...are some of the common features you might like. Learn and understand the difference between series 70 and 80 guns.../ what kind of guide rod do you want in the gun - one piece, two piece, GI rod... ---- some of the higher end guns will have features like a recessed slide stop, crowned reverse beveled barrels...high end finishes...etc...
As an example the Springfield TRP has all of those features and while it is available only in .45 acp ...its a lot of gun for the money and under $ 1,500. There are more and more 1911's availabe in 9mm...from Sig, Colt, Springfield and others.
If you have a chance ...at least look at the top end of the semi-custom 1911's...from Wilson Combat and Ed Brown...both very good companies, although I think Wilson makes the best gun out there. But there are a lot of companies making very good 1911's...( Sig, Springfield, Colt, CZ...).
What makes the 1911 - the best gun out there...is the trigger. The trigger floats in the frame and moves straight back and forth vs being suspended from a pin. Triggers suspended from a pin move thru an arc...and the best of them have longer pulls and longer resets. A good 1911 trigger should break under 5 lbs in my view...with very little slack and no creep. But for every production gun you look at ..you have to test the triggers and see how they came out of the factory....there can be a lot of difference in 3 guns in the case...
and remember to have fun with the process !!