Putting more efforts on those that have proven to drive results is a conventional wisdom in online marketing.

• Be consistent in building brand exposure on sites that have constantly driven visitors to your website - by becoming more visible on their sites through continuous content contribution or by making sure that the pages from their domain that passes on traffic to your website will continuously get traffic (by helping them rank better or by building 2nd-tier links).
• Update and solidify your site's top landing pages, particularly those that have low engagement rate, as these pages are the ones that help people discover your site/brand.
• Find sites similar to the websites sending targeted traffic to you and aim to gain more brand visibility from them too (given that they also cater to the same audience you're targeting).