1. Avoid travel by air if at all possible.
2. If you MUST travel by air, do not bring (all of) your best instrument(s).
3. Pre-arrange with the airline(s) to make sure your instrument(s) can be properly stored and cared for – carry-on is by far the best, but it isn't infallible. Get it in writing if possible.
4. Have someone you can trust to act as your agent at EVERY stop you must make, just in case the airline screws up and “loses” your luggage and you don't have time to wait for it to show up (sooner or later, they will and you won't).
5. NEVER describe anything you are traveling with as “bamboo” - Customs will freak out if they hear that word. Call it “reeds”, call it “cane”, call it “Arundo donax, of the family Poaceae” if you really want to be safe. The rules for Poaceae (grasses/reeds) aren't as insanely restrictive.
6. Have a detailed, notarized statement that fully and accurately describes your instrument(s), the materials it is/they are made from (use accurate scientific names), the age, monetary value, etc. and any other important considerations (like: “required for making a living”). Have this document with you at all times when traveling.
7. Don't EVER pack anything “suspicious” in the same bag as your instrument(s) – and please note that the definition of “suspicious” is extremely broad.
8. Exception to #7: if you pack and declare a starter pistol in the same bag, everybody will treat the bag with kid gloves and make SURE it doesn't get lost/stolen/strayed – they don't want to be responsible if some kook gets their hands on it and commits a crime with it.
Additional suggestions?