Does the campaign name makes sense?

Has the "From" name been added, and is it the best choice?
​i.e., make sure it is a name that those receiving the email would recognize 

Do you need a different "Reply To" address, and if so did you add the correct one?
​i.e., if you want the "From" email to be from info@ but responses should go to joe@ add a different reply-to address

Have you done a full check over...
The subject line? (access from Campaign and Sender section)
​The "From" name? (access from Campaign and Sender section)
​The preheader text? (access from Campaign Editor > Settings)
​The footer text and links?
All text and links in the email?
All images and buttons used?

Have you set up appropriate fallbacks for any personalization tags used, including personalized "From" names and email addresses?
​i.e., in case the recipient does not have a field completed this will ensure something else will appear where that field would

Do ALL images have "Alt Text" set?
​i.e., some email services will block images so the images "alt text" will appear in the images place

Have you checked the plain text version of the email for errors?

Have you sent yourself a test email, and made sure ALL your text links, image links and buttons lead to the correct place?
i.e., most templates with images or buttons will be set to link to your homepage or a blank website so it is important to check all links, images, and buttons

Have you had another person check the email for errors?

Is the email being sent to the correct lists/recipients?