Utilize a 1:3.5 ratio (i.e., 100px wide by 350px tall).
- Include a variety of products in your photographs.
- It’s best if your knowledge is as useful as possible.
- To encourage clicks, combine thorough descriptions with a call to action.
- Refrain from being overly promotional.
- Conduct A/B tests with promoted pins to improve outcomes (a business account required).
- Pricing details, endorsements, or a call to action are not permitted on promoted pins.
Source: Blog.Kissmetrics.com