Aside from leaving a star rating on the app store, leaving an actual review will help out void as well.
And if you can, take the time to tweet/retweet or mention it elsewhere on social media.
You can retweet the CDM article here: https://twitter.com/cdmblogs/status/696790778870394880
or the Matrix Synth mention: https://twitter.com/matrixsynth/status/696059545496350720
or retweet a link to the Synthtopia mention like Venn Diagram did: https://twitter.com/VennD68/status/696866556484128774