I have only done it once, but I used my dog's nail clippers. It has a stop to keep you from cutting too much off at a time (better control). I just trimmed the end off at an angle that looked like it would benefit her eating. The pale pink "quick" inside/underneath the beak is a blood vessel that is easier to see in lighter colored beaks. It extends close to the tip. You can cut close to the quick so that it begins to recede, and you may be able to trim farther back within a few weeks. Otherwise, the blood vessel can keep you from trimming off the desired amount.
Thanks! I just pulled her from the roost to try filing a little, to see if I can get everything to line up. Spoke with the breeder, and she swears this is the first crossbeam she's heard of from her line. That means it might be an injury.
If it's an injury, does that mean it might be correctable?