You may take a perfect picture every time. I sure don’t. I’m happy to have found SnapSeed, a dead simple photo editor. You can do all the things you expect: crop, adjust colors and brightness, sharpen, straighten–and do that all selectively. You can add a frame and various filters (even a vintage filter for you Instagram fans). Cartoon-like overlays show you what to do in each case.
Once done you can send your image to Google+, Email, Twitter, Facebook, or Open it in any app you have that can use images (including DropBox), or you can save it.
Best of all? The app used to cost $4-5 but is now free!