How to sing high notes

High notes fail when you push. They work when you support, lighten, and let the resonance do the work.

Tips

Support from below, not squeeze from above. Engage your lower abs on the exhale instead of tensing your neck.
Think "narrow" not "loud." A focused vowel and slight smile often unlock height better than more volume.
Use a lip trill or "ng" slide up to your top note — if you can trill it, your cords are cooperating.
Accept your passaggio. The break between chest and head voice is normal; smooth it, don't bulldoze through it.
Build range over weeks. Trying to add an octave in one session is how voices get hurt.

When to get a coach.

Range work is where bad habits stick fastest. A coach helps you add height without damaging your voice.