Prefix your object and table names with some unique ID

For instance, alphabeardmods_{id}, this will prevent namespace conflicts with official content and other mods in the future.

<?xml version="1.0" encoding="utf-8"?>
<objects>
	<object Name="ALPHABEARDMODS_CoolNewSword" Load="Merge">
       ...
	</object> 
</objects>

Only include your content and the minimum changeset via Load="Merge" in tables and object definitions

Don't copy the whole contents of the game xml. You only need to include new content.

For objects and encountertables, if you're editing an existing item you can use Load="Merge" in it's tag and only specify new items. For example, if I wanted my mod to give chain mail a 2DV:

<?xml version="1.0" encoding="utf-8"?>
<objects>
	<object Name="Chain Mail" Load="Merge">
		<part Name="Armor" DV="2" />
	</object> 
</objects>