Good morning :)

the two main principles that limes11 bxl-forever are hinting at are
https://wiki.openstreetmap.org/wiki/DE:Good_changeset_comments
and
https://wiki.openstreetmap.org/wiki/Changeset#Geographical_size_of_changesets

Please also take a look at 
https://wiki.openstreetmap.org/wiki/DE:Good_practice

When objects are removed in reality but are still visible at the usual aerial images please do not delete them. People at their computers will think they are missing and retrace the outlines. Take a look at
https://wiki.openstreetmap.org/wiki/DE:Lifecycle_prefix for more information.

I know that things here can be a bit (a lot?) confusing and complicated so please don't hesitate to ask others for help. Here are some places where people might be helpful:
https://wiki.openstreetmap.org/wiki/Contact_channels#Chats.2Fmessengers

happy mapping
silversurfer83