Communities share the same common symbols.
Symbols can include objects, ideas, words, phrases, people, signs, culture, language. Anything that has representative meaning exclusively to members of your community is a symbol of the community.
It’s almost impossible to deliberately create symbols. Don't try.
You do, however, need to know your symbols. Start a list; what has special meaning to insiders that wont have the same (or usually any) meaning to outsiders.
Then rank them by their prominence within the community.
Now reinforce your symbols frequently within the community.
Reference your symbols frequently in your content. You do need to help newcomers identify symbols and their importance. You do need to include symbols in the design of your community, the discussions you create, the promotion of your community, the events you hold.
Consider your symbols the branding of your community. They’re fantastic assets. You need to use them, wisely.