You need to have a clear record of what you did, what works, what doesn't!
Why?
Because if you get super good results with a certain script, you need to use that one more.
Stats are what keeps you on track and at the end of the month tells you if your strategy is working or not.
For how long should you test a strategy?
I would say a few days to a week.
You need to experiment to find out what works.
If after a few days, you notice that results are poor, step back and anlayse what you did.
Most of the times, you can easily pin point what is missing for you to succeed.
Discover what it is.
Implement some changes in your strategy and start again.
Giving up after the first attempts would be a key mistake.
Why?
Because cold calling requires a learning curve.
It means that you might get zero results one day, shift a detail in your offer and suddenly, orders for your services or products start coming in.