Use it when something small is very effective in achieving something bigger. Even an hour of volunteering each week can go a long way in making your community better.
Pro Tip 2/3
Positive Change
It's often used in optimistic contexts where the effort leads to desired improvements. Her determination will go a long way in overcoming her career obstacles.
Pro Tip 3/3
Avoid Overuse
Using the phrase too much may weaken its impact, save it for when something truly makes a difference. Study smart. Focused practice can go a long way in learning English.