All good suggestions!
A few others:
Rink chairs are fairly bearable, but if you are going to a competition like Liberty that has only bleacher seating, take something soft (and warm

) to sit in, or you'll wind up with a pleat in your seat.
Stay standing at the top of your section if you're coming back from the bathroom or concession stands until after the skater on the ice (if there is one) has finished their program. You don't want to distract them, or be rude to the other spectators.
If you are going to use a digital camera to take photos, bring lots of batteries-they run out faster in the cold.
If you are at a competition where it is OK to take videos, be sure to bring enough video cards. Check between warm up groups to be sure you have space for a whole warmup group. It's very difficult to change between skaters without missing parts of a program.
NO FLASH BULBS. EVER. AT ANY COMPETITION. Make sure you know what the camera policy is before you take one to the competition at all.
If you have hockey boards up at your competition, try to sit high up and avoid focusing through the glass. The glass will give you a different focus setting than no glass a step later. Fiddle with the settings on your camera for the best settings.
If you need a wheelchair or scooter, there are companies that you can find on line who will rent you one & deliver it to your hotel lobby, and in some cases, even to your hotel room.
Remember that for the Qualifying Round or SP, if you don't know the order of skate ahead of time, make sure to be in time to see the first couple of skaters. (At Europeans, that would have been Plushy! ) The first skaters are often more fun that you would think, in any case.
Check people's advice at GS about the arena you are going to. They often have great advice because they have been there before. If you have spare time at Colorado Springs, don't miss the cliff dwellings that are nearby.
If you're driving to the rink, check whether you have to pay for a parking pass, particularly if you want to succeed in parking in handicapped parking. This was a huge big deal last years at Nationals in Greensboro, NC. Get the pass early! They sell out quickly.
If you're planning on taking a shuttle, the last week before your trip, call the hotel and ask whether the shuttle really exists. Sometimes they turn out to be only for skaters, or don't exist at all.
You may be unable to get dinner that you can eat at some rinks. When you get home from the rink, you may be too tired to go out on the town. Before you book check that your hotel has room service, and check that room service will be open at the time you project to be back from the rink.
Some rink food is better than you might think! The food at Liberty is edible! Such a surprise.
Bathrooms. There is often a line at the ladies room that goes around the block if the event is well attended. Try to schedule a bathroom break or food break for less busy times.
That's all I can think of now.