* Follow normal circadian rhythm as much as possible. For me, it means I won't do morning panels but am happy to do late-night ones.
* Schedule time for meals. Carry snacks and beverages.
* Choose short activities or free-range ones. Most events will be ~45 minutes but some are shorter or longer. Many cons have a dress-up room, con suite, filk room, or other activities that people can walk in and out of as desired.
* Do not schedule more than two activities in a row. Preferably, alternate an activity and then a break.
* Avoid big crushing crowds. Visit the dealer's room during less-crowded hours. Watch the costume contest on hotel TV and/or enjoy hall costumes.
* Check if they have a quiet room, reading room, or other relaxing place. If the hotel doesn't, look for a nearby library, house of worship, or park as these tend to be relaxed environments.
* Get plenty of sleep. Never book a room on the party floor.