There are some very good threads about liquid soapmaking, and thickening in general. I recommend using the Search box in the upper right corner to search for "Thicken liquid Soap."
Thickening liquid soap depends on the type of oils used.
Use salt to thicken LS made with liquid vegetable oils like olive oil.
Salt will not thicken LS made with over 20% coconut oil.
Please read more here: