Q:

Ways to improve player retention

I've recently released my first free to play game on Android and I've spent a few £ on advertising to try and get players involved and see what happens.
Below are my retention stats courtesy of Google. Judging by the colour coding 50% is good <30% is not so good, but in reality I have no real idea what these numbers should look like. So this question has two parts really.
What are ok/good numbers for Days 1, 2, 7 and 30? So I know what I should be targeting, and what are good ways to increase my numbers to get the to that level. There are the obvious things such as notifications, but what are the less obvious strategies that a novice is unlikely to think of?

A:

I'll let someone with actual experience on Google's retention stats for popular games and so on answer your first question.
As for the second question, the short answer is to design your game with retention in mind. Your goal is to make the player come back to your game and your game should try to make him come back as part of its core.
Things you might want to keep in mind and apply based on your situation (in no particular order):

Avoid things that make your game a chore to play through (i.e. make a fun game). Examples of such things are very slow loading times, very poor performance, crashes, bugs, poor controls, huge amounts of work for very little reward (tip! you might want to let your player be able to achieve something instantly when he comes back to your game. It doesn't have to be something huge) and so on.
Balance the difficulty accordingly, don't make your game frustrate the player. See this for more on the topic:
What is an optimum failure rate that will keep people coming back to my game?
Do not annoy the player. Begging for him to come back or harassing him is annoying.
Periodic notifications are good. Don't exaggerate, otherwise you'll annoy the player. Make notifications meaningful, otherwise you'll annoy the player. Making it obvious that your game is nagging him to play some more each day is a sure way for the player to uninstall the product.
Introduce time/duration based mechanics. Make a house take a while to build, and the player will return later on to see it finally being built and start building another house (hopefully).
Introduce periodic special events. Let the player know that one week from now something awesome will happen and he has to be there to see it.
Update your game often, add more content. Dead games are not favored by players who are looking for games to play long-term.
Try to build a community around your game. Integrate social networking services. Raise some hype. Make your players talk to each other. Letting the players make friends within a game is a great way to make them come back to your game and interact some more. Communities tend to keep games alive for a very long time.
Make the game look like it's been made for the player that's playing it, not for some category of players in which he has been thrown. That means you should let the player personalize his experience as much as possible. He's much more likely to keep a game that feels like it's "his". Custom loadouts, custom avatars, custom names, custom signatures and so on, all can be used here. Translations also help. Making your game speak the player's native tongue may go a long way towards him liking it.
Don't be afraid to try a new strategy with a new game if you see your game is dying. Any hot game cools down eventually, so having some new ideas with you at all times is mandatory to survive anyway.
Track the players' activity in your game. See what they do most often, what they like and what they don't. Optimize your updates according to the data you get.
Use what you've learned with your previous games in your new games.
Talk to your player and let his opinion matter. Planning a nice update? How about asking your players what they want? Use polls, or even better, ask the player questions directly in the game: "What would you like to see in the next update?" Use the feedback to plan your content accordingly. At the same time, you let the player know he's being listened to, and he's more likely to come back to your game to see his ideas become reality.
This may or may not be cost effective in some cases: make as many of your key mechanics for retention as possible work together with a server on which you can customize their properties. Want to update the price of certain consumables and advertise it as a sale? Just set the properties (values, start date of the sale, duration of the sale and so on) on your server, and all of the games will automatically adjust according to them. This ensures you'll always adapt quickly to new situations.

