The sign for strawberry has several versions. Check with your local Deaf or ASL instructor for what is preferred in your area. The version I show below is a good, widely recognized version.
This sign is the general sign for "strawberry." But it can be used to mean "berries" in general.
STRAWBERRY / BERRY:
Notes:
Suppose you wanted to sign the concept of "blueberries." You could do the sign BLUE and then do the "STRAWBERRY" sign and it would mean: "blueberry."
So, the default meaning of the "BERRY" sign is "strawberry" but if you add BLUE at the beginning it changes to mean "blueberries." You can hold up an "R" and then sign BERRY and it will mean "raspberries." You can spell "goose" and add BERRY to mean "gooseberries."
Notes: