When a user looks for an Android app in Google Play Store, a number of apps appear in a specific rank. Mobile apps with higher ranks are more likely to be noticed and downloaded by users. The goal of this work is to understand the evolution of ranks and identify the variables that share a strong relationship with ranks. We explore $900$ apps with a total of $4,878,011$ user-reviews in $30$ app development areas. We discover $13$ clusters of rank trends. We observe that the majority of the subject apps (i.e., $61%$) dropped in the rankings over the two years of our study. By applying a regression model, we find the variables that statistically significantly explain the rank trends, such as the number of releases. Moreover, we build a mixed effects model to study the changes in ranks across apps and various versions of each app. We find that not all the variables that common-wisdom would deem important have a significant relationship with ranks. Furthermore, app developers should not be afraid of a late entry into the market as new apps can achieve higher ranks than existing apps. Finally, we present the findings to $51$ developers. According to the feedback, the findings can help app developers to achieve better ranks in Google Play Store.