What are email design best practices?

Email design must balance brand expression with technical constraints. Unlike the web, email renders differently across hundreds of client/device combinations. What looks perfect in Gmail may break in Outlook.

Core best practices: Single-column layouts for reliability (multi-column for desktop-optimized sends). 600px max width for broad compatibility. Web-safe fonts with fallbacks. Images with alt text (many clients block images by default). Touch-friendly buttons (minimum 44x44px tap targets). Clear visual hierarchy (what's most important?). Consistent branding (recognizable at a glance).

Design for the worst-case scenario. How does your email look with images off? In Outlook 2013? On a 4-inch phone screen? In dark mode? The email that works everywhere outperforms the beautiful email that breaks for 20% of recipients. Test across clients using tools like Litmus or Email on Acid before sending.