Split testing has been known to drive some pretty compelling results, but that all assumes one thing: that it's done correctly. There are numerous aspects that you can look into for split testing, and they can get complicated. I'm here to make things clear for you.
So, if you want to run an A/B test accurately and get long term results, you need to do these 3 things first:
Have a Clear Goal: is your goal to drive traffic? Is it clicks? Or even opt-ins?
A clear result is determined by setting a clear goal at the start. An email subject line that wins at an open rate may be different than the winner for click-through rates. Define your goal first.