How to improve PPC Conversion Rate?

Hi,

Suppose you're ruing PPC (Google and Facebook) campaigns and you have tools like Google Analytics. How would you improve the conversion rate of those campaigns?

What I'd do - tell me if there is anything else you'd do:
1. exclude non-converting traffic (only after 2-3 weeks, taking account of the fact that there is consistent traffic coming in)
2. optimize audiences and targetings (excluding anything that doesn't convert: age, gender, behavior, context/topics etc.)
3. A/B test ads:...

How to improve PPC Conversion Rate?