At Exclaimer, we see a lot of email signatures. We see what a lot of companies get right and what they get wrong.
DO use tables
Using tables lets you know exactly how wide the signature will be and that each part will appear in the right place. This means no job titles getting squashed together or images appearing inexplicably in the wrong spot.
Remember, you can simply leave the borders transparent if you don’t want to see a grid, so we’re just talking about using them to place each part of your design.