Using the Shuttle Bus
There are numerous shuttle bus routes available, which means that you can park your car in a lot and commute without the hassle of traffic. There are free hybrid shuttles functioning at the Valley floor and buses to Tuolumne Meadows or Glacier Point.
Riding a Bicycle
Bikes are the most interesting means of getting around Yosemite, especially near the Valley floor. Aside from helping you avoid traffic, it will allow you to easily stop and take pictures. Plus, you get to soak in the surrounding scenery as pedaling is slower than driving.
The simplest way of moving around the park is to simply walk. This will truly help you stop and smell the wildflowers both literally and figuratively.
You are also welcome to drive your car within Yosemite National Park. However, make sure to avoid using GPS as it can mislead you. In addition, comply with the 25-35 mph speed limit to protect the wildlife and avoid traffic issues.