Some great fundamentals here that are often missed! Always surprised at how many people don't check/change the auto-generated text version (note this can be risky as it won't necessarily pull through your whole email correctly - especially if you're using variables to populate some sections).
I often find them to be neglected or forgotten. And even people who were taught to make the changes don't necessarily know why or what it means in the inbox!
Don't forget the fundamentals! No matter how complex your marketing efforts become, if you neglect the basics you could be missing your easy wins and the little pieces that are the building blocks for long-term success.
It's so easy to forget to make sure the plain text email looks nice! Good reminder to have that as part of your overall checklist.