It doesn't have to be a prefix

Don't just stick a hyphen between "mini" and the word that follows.

"Mini" is a great prefix (in which case it's set solid or attached with a hyphen). 

But it is ALSO an adjective, all on its own. (In an adjectival state, it stands alone).

And sometimes the adjective is what's needed! ("Big dreams and mini budgets," for example)

Dolls wear mini skirts.

Tarts wear miniskirts. 

Soccer moms drive minivans.

Their sons drive mini vans.

Peter Callahan makes mini treats. (Tiny little cheeseburger, etc.) Not mini-treats