Put the tahini in the measuring cup or bowl. I find it easy to mix in the measuring cup because I can measure amounts so easily.
Add the lemon juice to the tahini. Mix well. You may find the mixture gets very stiff, but keep at it, it eventually mixes. Add a bit of water if you need to to make it smooth.
Add the rest of the ingredients, except the water. Mix well.
Add water until the sauce to thin to your desired consistency.