It is critical that users can easily find your App on Google Play, and this can be achieved by following these tips.
Probably the most important place to have relevant keywords. The name of the App is likely what is published in marketing and PR material, and is therefore the most obvious search criteria for a user to discover your App. Its really important to think about what a user is likely to type to discover the App. For example inserting a brand name when a user is unlikely to search for it doesnt make sense. So if the brand name or title wont resonate with users in search, consider using more descriptive terms in the title. This is often the case for startups.
Keyword search is driven by the description in Google Play. Unlike the App Store where keywords are explicitly entered in a Keywords field, Google instead looks for keywords in the description string text. Consider repeating a term multiple times (no more than 5 and always in context).
To ensure a high conversion rate to download once a user has landed on your App page, striking artwork is a must. This starts with the App icon that should follow all the way through to screenshots, video and ensure feature artwork has been submitted (improves likelihood of being featured). This is a great start http://developer.android.com/distribute/tools/launch-checklist.html
A great experience
The rest is completely up to the App, and its appeal to the marketplace. Apps that make a users life easier, are designed to best practice and are completely reliable…. get better ratings, more downloads and continued usage and engagement from users. This is by far the most effective way to continue to drive search-ability and downloads well into the future.