1. Move most of your media consumption over to the new language. Movies/books/internet/twitter/etc..
2. Plan on an hour a day of active study 3. Learning phrases is much more effective than learning words, although eventually you will need to do both
4. Learning by audio is much better than reading
Lately just for fun I been working with unreal engine. You can do some really cool stuff quickly and customize in C++.
Now that VR is becoming in bigger and bigger might be marketable some day. That startup magicleap seems to be doing lot of stuff around this area.
Can pair unreal with houdini and do some python scripting / 3d math learning.