Tips and tricks to installing cabinet doors and mounting hinges
Euro style hinges adjust in all 3 directions that you'd want: up/down, in/out (relative to the cabinet wall), and front/back.

If you start with a cabinet carcase that's square or nearly square, it's usually a matter of tweaking some of those 3 adjustments on the hinges. (If the cabinet is desperately racked, you might exceed the adjustment range of the hinges. In this case, you need to correct the cabinet, then fiddle with the hinges.)

Note that the screws on those hinges are often pozidrive, so if you're doing a lot of this, you'd do well to get the right screwdriver. (Failing that, use philips, but be careful about stripping the screw heads.)