General advantage:
* Have the upper hand: This implies a position of control or dominance.
* Hold all the cards: This implies having the power to make decisions and dictate outcomes.
* Be in the driver's seat: This implies having control and direction.
Specific advantages:
* Get a leg up: This implies a head start or an opportunity to get ahead.
* Have a head start: Similar to "get a leg up," this implies an advantage in starting before others.
* Get the inside track: This implies having privileged information or access.
* Hit the ground running: This implies having an advantage due to preparedness and efficiency.
Informal:
* Be ahead of the curve: This implies being innovative and forward-thinking.
* Have a winning edge: This implies having something that makes you better than others.
The best idiom to use will depend on the specific context and the nuance you want to convey.