You might be building out an email that looks great as your building it, but what does it look like for the recipients?
Every email client works a bit differently, and this can cause havoc on html emails that are going out. This occurs as each email client renders html and css differently.
Ex. Outlook doesn’t support padding but Hotmail doesn’t support margins.
This is why you want to test your email structure in lots of environments, and on different devices. If you do not have the devices at your disposal you can always hire someone, or use a service like litmus to see how your email is going to look.
Now to reduce the risks of having problems and get the best results, make sure you email is built by someone who understands the best practices for building HTML emails. Feel free to contact me to discuss how to make your html emails better.
Image source from http://freshinbox.com/blog/gallery-of-outlook-rendering-issues/