There are many more resources outside the scope of this tutorial that may be useful to you. Some of these are ATLAS-specific, and some are more general-purpose. We have compiled some resources here that you may find useful as you continue to learn.
The ATLAS Computing and Software TWiki is the go-to resource for all things related to computing in ATLAS.
The ATLAS C++ coding standard is crucial in making sure that our code remains easily readable (and therefore extendable) by the collaboration.
The following are some useful ATLAS-specific tutorials.
Take a look at the HSF Curriculum page for links to these trainings.
The PyHEP working group (from HSF) brings together a community of developers and users of Python in Particle Physics, with the aim of improving the sharing of knowledge and expertise
Other useful tools used in the HEP community are: