Wash and optionally trim off the crown and strawberry leaves with the tip of a knife. This is not necessary as the leaves are edible, but they can add a slightly bitter taste. We always leave them as they are very nutritious.
Place the strawberries in a high-speed blender, and add water and lemon juice. Blend for 35 seconds.
Optionally sieve the liquid with a fine-mesh strainer. I don't find this necessary at all as there is very little pulp left, but some people like their juice perfectly thinned. I recommend you to try it and this point and see if you like the consistency.
If your strawberries are not very sweet, you might want to add a tablespoon of agave syrup or any natural sweetener. I find agave syrup to be the most neutral sweetener when I don't want to affect the flavor of the juice.