Hi!
I have a quiz game that got more than a million downloads. Got very lucky on launch (before last christmas) and I still get more than 1k downloads a day. And it has been great. 
I’ve launched other games since then, but nothing sticks! I’ve tried cross promotion but it doesn’t seem to have almost any effect at all.
Have you guys tried cross promotion from a somewhat popular app, what’s the most effective tactic you’ve had?
Thanks
The more similar the new game you want to promote the more effective the cross promotion. Try releasing a sequel 
Getting reviews from popular and reputable bloggers will help improve the performance of your cross promotion campaigns. App users love downloading a product which actually works and which can help them do whatever they want. For instance, if your app is about certain kind of a game, you have to ensure that it has all the features which someone playing that particular game requires. You may also ask the bloggers and website owners to include a link in their pages and give them something in return. This will help in enhancing the number of downloads which you will achieve with cross promotion.
Cross promotion helps so much. You see mostly paid application links are give on other free games on Google Play store, this helps to get relevant traffic from a relevant platform. Also you can promote you application by writing and publish articles review on different site for more installs.