At any park, especially the big national parks, your first stop should be the the visitor center, where the staff generally have on-the-scene knowledge of the nature and state of the attractions. They can tell you where wildflowers are blooming, elk are rutting, and waterfalls are surging, and can provide an up-to-the-minute weather forecast and the exact time of sunrise and sunset. They can inform you about campsites and road closures, too. Spend some time at the bookstore browsing picture books, calendars, postcards, and posters to get a feeling for the park's overall surroundings and conditions. This will not only inspire you but also help you formulate your park visit.