App Store Optimization (ASO) is still a nascent field, and a lot of the strategy around keyword stuffing and title manipulation feels like SEO from 10 years ago. While the weight and importance of keywords (other than title) may shift over time, there are two other factors that will likely carry weight in perpetuity: Install volume and app ratings.
If you develop iOS games, you know that install volume depends a lot on strategy and a little on luck, what with paid users becoming more expensive by the day (approaching $3.00 on average), and App Store newsstand placement almost 100% editorial at this point. Thus, organic discovery is one of your most efficient ongoing acquisition channels, and for that your ratings matter. A lot.
Ask players to rate your game
All too often great games will show horrible ratings in the app store for one simple reason: Happy customers are busy playing your game. Only angry customers (like that guy trying to run your gorgeous MOBA on his iPad 2 that keeps crashing) rush to the App Store to tell you what they think, and it ain't pretty. You shouldn't ignore these folks, they're giving you important, critical feedback, but for the sake of truly reflecting your users opinions, you need to get your loyal players contributing their positive voices as well. Do this by asking your players to rate your game.
Make Sure They're Happy First
Don't pop a system dialog rating request the minute someone starts a session. As with any dialog requesting something of value from the user, wait until a moment of positive engagement: A moment where they're likely to feel good about your game and have good things to say about it. Victory screens, level-up moments, awards and achievements can all be great times to ask for a rating.
Some games will even use a two-stage rating prompt asking a user what rating they would give the game, and moving anyone who wouldn't rate the app well into a customer support feedback funnel. Here's an example from the game Dungeon Keeper:
Step 1: Ask for the rating:
Step 2: Send low ratings to feedback funnel:
The two-stage rating prompt can be good, but you're also adding an extra click to the flow for positive users. Critical feedback is a high-value problem though, so two-stage can be worthwhile if you have the support resources to use it effectively. In a perfect world, test single-stage and two-stage and see which drives better rating activity.
Encourage Five-Star Ratings
One thing you may notice in the example prompts above is that they both use five-star imagery in their designs. This is not an accident. Once upon a time, you could pre-fill the rating when you took a user to the app rating screen. This is no longer the case (probably for the best), but you can still encourage the user to give you the rating you'd like. In this example from Draw Something, the prompt explicitly asks for 5 stars.
While I always encourage you to test and optimize your designs, I'll save you some time here: I've tested prompt designs with and without stars in many games across different genres and stars perform better every time.
Building a high-quality rating prompt in your app will significantly increase both the number and quality of ratings you get for your game. I've seen rating volume increase 20x and overall ratings go from 1.5 to 4.5 stars overnight by implementing a rating prompt strategy. This is a simple and effective way to help overcome a handful of negative reviews and, more importantly, help boost your organic discovery and ASO.