As a part of their Material Design Google has released a great set of icons. You can import the whole library or just the icons you need for you project. The icons come in many sizes, so it is easy to cover different size screens.
A main focus of Google has been Material Design, these color palettes work well with other projects also. It’s easy to find a nice shades in different colors, that you can use together.
A video from the Android Developers YouTube channel about live templates, which are snippets of code you can easily use again. Only write the correct start and then press start.
A video from the Android Developers YouTube channel about practical app development and trying out things first before being too concerned with the right architecture of the program.
Udacity is a site with free and paid online courses on a variety of software development topics. The content is made in co-operation with Google and is very clear and informative. The courses include exercises and downloadable projects. The courses are also a lot less verbose than some online courses, so it’s more actual coding and less watching videos.