I don't have any rituals, but I have gone from the days of practically blowing chunks to being very relaxed...
First... Don't run a dog until it's ready. If you know your dog is ready, then what do you have to worry about? If the dog fails, the failure will be "legitimate" and NOT because you and your dog did not prepare for the test.
Second... ACCEPT that failure may occur and that you or the dog may screw up. After Joie died, I was petrified about what I was going to do with my future. I read a great article that said "accept the worst outcome" and then anything else that happens is ok. So I thought "worst case, I send all my client dogs home, let my house foreclose and move back with my parents or in with someone who will take me"... I could live with that if I HAD to. So typically the worst thing that will happen at a hunt test is that you will fail. You CAN live with that even if you don't want to. So take a breath and realize it may happen, even if you're going to work hard to prevent it.
Third... Know YOUR dog. Look at the test and examine it in terms of YOUR dog. Every test I run, I can quickly tell what will be the KEY areas for each of my dogs. One has the propensity to out of control in scent en route to a blind. Another will overshoot short birds. FOCUS on the KEY areas. Don't worry about the WHOLE test. Your dog will NOT fail the WHOLE test. Focus on the areas you really need to plan for.
Fourth... KNOW that your dog is NOT every other dog out there. You saw the last handler send their dog in a strange order? You saw another handler cast their dog a certain way? Guess what? That is NOT your dog! Don't be tempted to do what other handlers do. KNOW how to read and handle your dog based on YOUR DOG. Use any observation of other handlers to pick out the difficult parts of the test, figure out wind direction at various falls and other areas, know where scent is an issue, judge terrain/cover/water changes.
Fifth... KNOW the test. Watch test dog. Listen to the scenario. Don't be afraid to ask questions.
Sixth... Confirm the test and instructions with the judges prior to leaving the holding blind. If the test is anything but straightforward, confirm the order of marks/blinds/honoring etc.
Seventh... SLOW WAY DOWN. Think you're already moving slowly enough? Slow down EVEN MORE.
Sixth... Take deep breaths while you're working your dog and handling. If you start to feel stressed, relax your muscles and breath deeply ENJOYING YOUR DOG's WORK!!
Finally... Try to never take your eyes off your dog. At the same time, be aware of your surroundings and anything that may impact your dog's performance.
Hey, I think I'll make a book out of this.
Hope it helps.
-K