I would like to hope that someone's small business is going well.
I know if someone's business is going well they can say:
「店は繁盛している」
but, how can I say "I hope your store is prosperous/I hope business is going well"
Maybe, just add 願う 'hope' or 祈る 'pray'.
お店の繁盛を願っています/祈っています