Sorry, no tips and tricks, but I just wanted to add my voice to those calling for an improvement in the certificate design process. Anyone reading this who hasn't already voted, please consider adding your vote to the following idea:

I agree the Template Certificate process needs to be simplified.  Is see this ide was merged with this one, and now it’s closed.

My issue is that there should be the:

1) ability to copy a certificate template

2) ability to save/download the background image for subsequent use

I love the comment in the certificate template

IMPORTANT: Due to a limitation of the PDF class which will be fixed in a future version, we suggest using ONLY background images and not embedded images in HTML code inside tags like < p >, < div >, < center > etc., as this can cause errors.

“which will be fixed in a future version”  sure … maybe one day !!!