Choosing the right pond to suit you and your garden is the first step. A natural pond, rich in native plants, can become a haven for dragonflies, newts, frogs and toads. Such a pond may not be ideal for keeping fish requiring a different environment which may include plants to provide shade for the fish and link the garden seamlessly to the water. Formal or informal you should consider a fountain or some other moving water feature to add this extra dimension. The location should be planned to include some shade, particulary at midday, but avoiding the potential problems caused by roots or falling leaves.
Conifers can be good as they provide shade, shelter with less risk from falling leaves.
Also bearing in mind the practicalities if you need power supply for pump, lighting, etc. Designing your pond Ponds always look smaller when in the ground. Therefore, plan for as large a surface area as possible. A minimum depth is 18 inches although 2ft. Consider your planting and provide a shelf 12 inches wide by 9 inches deep.