Some simple things in the campaign management can substantially boost the performance of your campaigns and yield you more conversions. It's good to know that for performance conversion rate (CVR) is a more important metric than click-through rate (CTR) since clicks don’t tell the whole truth.

1: Be Bold and Bid Higher

Even though it could sound a bit irrational, a higher maximum bid generally improves both delivery and return on investment (ROI). With a low bid, you can reach people who are more easily reached but who don’t necessarily provide the ROI you expect. It's also good to keep in mind that in Facebook auction you'll usually bid less than your maximum bid,

2: Use Larger Audiences when optimizing towards actions

Facebook bidding algorithm identifies people from your audience who are most likely to take a specified action--e.g., purchase a product at your web store--on your ad. However, the algorithm needs huge amount of impressions, clicks and conversions to work properly. Use larger audiences and higher bids to fix the issue.

3: Ensure you have enough conversions for your optimization goal

Optimizing bidding for actions requires a conversion rate (CVR) of 0.5 % or more with a 1-day click-through window to work effectively. If you have trouble getting the minimum required conversion rate, you can consider combining ad sets to increase the number of daily conversions coming in to give Facebook optimization more data.

4: Prevent ad fatigue

If the same ad is shown too many times to the same users, it loses its power. This is known as ad fatigue. The ad frequency gives you an idea about ad fatigue. You can try to tackle the ad fatigue by:

• Changing your ad creatives periodically - see more at Ad rotation.
• Having larger audiences.
• If your reach is small compared to the reach estimate, increasing the bid is likely to help

Also, Relevance Score can help you understand the quality of your ads.