Remember to add plenty of associated planting round the edges and nearby as well - it's vital for emerging frogs and small creatures to have cover close by
An oxygenator is needed - there are several readily available, and a few marginals on the shallower parts, including a vertical is all you'll need if it's a very small pond. Choose appropriate plants - many are designed for larger areas and will take over.
My pond here is tiny - around 1 metre by half a metre, but it has a sloping beach for access and a couple of vertical plants as well as several others at the edges, including a white Caltha (marsh marigold) a spiral rush and some chrysographes irises, leading into taller cover. I also have a tiny water lily in the deepest part. It's been well used in the 18 months it's been there