You can use the tried and true high note systems from Mastering Clarinet High Notes to improve how you sound on your highest notes, and feel more at ease as you play music that takes you into higher, faster, notes. Most common high note frustrations (squeaking, "loud" sound, not coming out at all, shrillness, slower fingers) can be cured if you know how to do it. The solutions are usually not very complex, and you can usually feel pretty comfortable with new skills after a few weeks of training. Enjoy these videos to give you a sample of some of these systems to make high notes easier for you.
There is so much valuable training here. Here is a time index to help you find the topics that most interest you. This is especially helpful if you refer back to this video later to try these on your clarinet.
2:54 - Is your reed the best strength to help you play high notes?
7:37 - Do you know how to blow your air to best support high note tone?
11:42 - Here's a great exercise to do with a clarinet-playing buddy
12:45 - Do you have this super-common bad habit that causes squeaks, or makes high notes resistant to playing?
13:36 - What should you do with your tongue when you aren't tonguing, and how does that affect high notes?
18:39 - How are hand and finger position affects how easy it is to move from low notes to high notes.
21:20 - Special Clarinet Gym Exercise to help your hand move better on the clarinet
24:52 - How your brain may be creating extra trouble for you, and you don't even know it!
27:30 - How we all have those critical "failure" moments, and how to overcome them.
What Is Your Biggest Challenge With High Notes?