Bitrix: how to properly customize the component template?

Question

1C-Bitrix

People! Tell me how to properly customize the component template:
1) Take a standard component and insert your layout there (then: can there be something extra there?
I look: a bunch of checks, Ifs, etc.)
2) Take the layout and throw it there what you need for the task (how not to forget anything from processing properties??)
I want to learn how to do it quickly and correctly, and not look for, fix jambs after layout integration ....