Round or Oval?
Bigger can cost a lot less than you think
What height of pool do you want: 48" or 52" or 54" tall wall?
What size pool and shape best fits your backyard and your family?
The wall color and pattern may or may not be an important to you. If you plan to add decking around the pool, you will be covering much of the decorative wall pattern. You might consider allocating more dollars towards a decorative, quality liner and less towards what the pool looks like. (Most pool walls are neutral grey or beige.)