Some quickly tips and commands to start with Android hacking
Decompiling apk
apktool d -s <your.app> -o <your output folder>
Look for API keys and clues on AndroidManifest.xml res/values/strings.xml
Look for databases
find . -name *.sqlite
find . -name *.db
After unpacking if there is classess.dex file you can use this tool to convert from dex2jar. Just download project and unzip it. If you are on Mac or Linux make sure all .sh files can be executed :) chmod is your friend…
./d2j-dex2jar.sh <your dex>
jd-gui is small app that convert java binary to readable format
That’s it. Simple tool to start android hacking :)