Your pond need not be deeper than 1 to 2 feet, unless you're planning to stock fish. Minnows are excellent mosquito larva eaters. Goldfish are bottom feeders. To prevent puncture, put a protective underlayment between the ground and your liner. As the newspaper slowly decays, it actually forms a watertight substance called gley.
Concrete contains chemicals toxic to aquatic life.
Scrub concrete ponds with muriatic acid and rinse thoroughly. A lined pond should have a free-form shape. Gradually sloping, rocky sides provide niches for plants. A log connected to the shore will serve as an escape route for small mammals that fall in and would otherwise drown. Hide the pond edge as Nature would.