App Store, like Google Play, never officially discloses the nuances of its algorithms. However, some features can be found empirically. The most significant influence on the product position is exerted by name; subtitle; keyword field; URL; in-app purchases. The first three items are ranked by algorithms and have the biggest impact on apps ranking, so they should be the best optimized. Using the App Store features, you can increase your visibility. You can offer users up to 20 in-app purchases.
Each item has an indexable title and description. If you distribute your app across multiple regions, take advantage of localization options. Another developer-friendly feature is user activity tracking. Lots of downloads and launches show the high quality of products, and, therefore, the algorithms perceive them as trending apps and show them more often.