Best Practices for Meta Title and Description

Title

• Remember mobile-friendliness! Keep your character count around 60 characters, or else Google will cut it off with ellipses (...)
• Use important keywords that reflect the subject of the page
• Put important keywords first or as early as possible and your branding in at the end
• Write a unique title for each page that closely replicates (but doesn't duplicate) the H1 of the page

Description

• Always keep character count in mind - keep it around 155, but no more than 160
• Just like titles, keep each page's description unique to that page and put the most important keywords up front
• Consider it an ad - write compelling copy with both your branding and calls to action
• Heads up: Google won't always use your exact description as they may pull in content in the page that is most relevant to the searcher's query