Work like a charm
Definition 1 of 1
Pro Tip 1/3Positive Outcome
Use when something works better than expected and you're impressed with the results. 
I was skeptical, but the new strategy worked like a charm in increasing our sales.
Pro Tip 2/3No Troubles
It implies an action or method is not only effective but also free from problems. 
Switching to the new software worked like a charm; no issues at all!
Pro Tip 3/3Informal Context
This phrase is typically used in casual conversation rather than formal writing. 
When I lost my voice, grandma's home remedy worked like a charm.