It depends on your industry, but as I am in lead generation, I will say that those are the most important points:
grabbing attention from the right prospect is key
making sure friction is low; ex: filling the form must be easy
on your creatives use flashy colors, big text easy to read and simple words
for your text copies, start with a hook, then a fear, a benefit, then end with a call-to-action
as for audiences, don’t choose just 1, run many tests for broad, interests, and lookalikes; and re-run those tests every other weeks/months, as the algorithm changes over time！
