Know what you want. 

The way your pond is built depends greatly on why you are building it. That is why we categorize them the way we do. Find out if you want a water garden, goldfish pond or koi pond before you start.

Do it yourself
Resist the tendency to focus on the work that needs to be done before thinking through what the finished product will look like. Your project will be more successful if you know what you want to achieve before you start.