Make sure you let someone know where you are going, and when you expect to be back. Carry a hat, sunscreen, sunglasses and weather-proof jacket in all seasons. Take plenty of water, and more food than you think you will need in case you get caught out longer than you expected. Wear sturdy walking shoes/boots.
fees/permits
There are entrance fees to the park, and permits and fees required for overnight/multi-day hikes.