"But ... all of these signs look the same?!?"
The signs for DRY, CEREAL, BECAUSE, SUMMER, and BLACK seem to be confusing people, like a lot, so here they are all in one place so you can see the difference between them.
Begin with your dominant index finger on the opposite side of your face, as you bring it across your face near your mouth change your finger into an "x" shape (only once).
Start with your dominant hand on its respective side of your face, alternate between a "1" and "x" a couple times as you move it across your face, right by your mouth. This motion will be right to left if you are right hand dominant.
Start with your dominant index finger touching your forehead and then bring it off of your forehead curling it inwards.
Change your index finger from a "1" to and "x" as you drag it across your forehead.
Move your wrist, not your finger. Drag the tip of your dominant index finger across your forehead, near your eyebrows.