Keyword is the most important thing for app store optimization. So you have to chose your keyword very wisely. As we know what keyword do, so don't go for it. I just point out some key features while we do keyword research. Put your tittle in keyword, for example if your app name is "Cannon Shooter : Clash for Love" you should use all the word as a keyword like - Cannon, Shooter, Clash, Love. Use the singular and plural word, for example if you use Game as a keyword use the plural word "Games" also on keyword. Try to use Some joint word, for example if you use Free and games as keywords, don't separate them by comma. Use these two word as a single keyword, like - "Free games". Joint keyword will give you more specific search result. The most important thing, find keyword which is relevant to your app. One bad practices but effective, Find some similar game which have grate active users or which have been getting downloads than use their tittle with out any comma separated word on keyword. for example if your game is similar to "clash of clan" use the full tittle on keyword like- "Clash of clan" not like "Clash, of, clan". Please if yo have any other idea add on comment.