Blend all ingredients, EXCEPT for the soap, in a blender. Why not add the soap yet? Well, if you did that, you'd create a whole. bunch. of. foam. Ask me how I know. (Aren't you glad you get to benefit from the finished method, instead of mucking around like I do?)
Now smell it. See how you like it, if you want to add more essential oils, or different scents. Now is the time to do this, while you can still blend it up before adding in the soap.
Lastly, add the soap and blend on low speed just long enough to mix everything together well.
Carefully pour it in your bottle. If it still ended up a bit foamy, you might just want to let it settle before putting the lid on.
Once the lid is on, pump it a few times to get the foam going. See how thick the foam is, try washing your face with it. At this point, you might be content with the foam texture, or you may want to thin it out slightly by adding a small bit of water. If you do add more water, don't blend it up again. Just slowly add some water to the container, put the lid on and gently mix it around a little (don't shake it!), then try pumping the foam again.