Android is not as hard to work with as people think, it just requires a little more effort!
The best place to start looking is the actual Android design guidelines which can be found on the Android developers site but it's designed purely for Android designers.
The basics are:
- Android is broken down into different "versions" which are exactly the same as iOS's versions insofar as they are when new iterations have been released, (like iOS 6, iOS 7 etc), these are named two ways, by a number system which donates the version and the iteration (like in computer software, so you'll have version 4 iteration 4 or 4.4) and by a little name to make it easy to diferentiate (like Ice Cream Sandwich or Kit Kat, not dissimilar to the way Apple names it's Mac updates)
- As Android can run on a variety of handsets there are lots of different screen sizes to take into account (you can see the most common ones here, the site is updated every two weeks). However it's not the screen size that determines how much will fit on the screen but the size and density (resolution for lack of a better term). DPI is basically a way of telling how big the screen is, an MDPI screen fit less elements on it than an XHDPI screen, regardless of the physical size of the screen. However, this isn't something that most UI/UX designers need to worry about as they only need to be aware that their design won't look the same on every device.
- Designing for Android is not dissimilar to designing for responsive web, things will change because of the screen sizes etc but also you don't have seperate apps for tablets and phones but one app which re-arranges the screen using something called fragments (in it's most basic form each screen is a fragment and when working on a tablet you can put two or three phone screens next to each other).
Android phone screen showing a list view which would lead to an item view
Android tablet screen showing list view and item view
- Android uses an action bar which allows the most commonly used actions to be placed at the top of the screen in an icon format.
- Reading the Building Blocks page of the Android Design site can give a basic overview of how Android works
There are a couple of sites which give you an overview of how to go about designing for Android
- Smashing Magazine has a great article on Android design, it's a little old but it explains the basics very well
- Mobile Smashing Magazine also has an in-depth look at how to design for Android
- Meng To has some insights onto the differences between iOS and Android
- I have a list of things to do AS you design to ensure that you don't become de-railed.