The most important thing to note when running paid traffic is that cost per click divided by conversion rate gives you your CPA.
Which means, you need to...
1) Lower your CPC
2) Increase your conversion rate
You can increase your conversion rate by...
1) Improving your offer
2) Improving your ad copy
3) Make sure your landing page is congruent with your ads
4) Changing your strategy entirely
You can increase your CTR and lower your CPC by...
1) Making ads that speak to a buyers awareness level
2) Increase curiosity
3) Ensure a hook rate above 40% if running a video ad
Hopefully that helps!