Headlines:
0. Start with learning B4i main concepts.
1. Organize the code in classes.
2. Use the designer for the layouts.
3. Use XUI wherever you can.
4. Learn how to share modules between projects.
5. Learn how to share files between projects.
Relevant video tutorials:
https://www.b4x.com/etp.html
2 * XUI videos
B4i / B4J Resize event
Cross platform tips:
https://www.b4x.com/android/forum/threads/96815/#content