Design a UTM naming convention for a new campaign

I'm planning a campaign called "Diwali Sale 2026" that will run across these channels: Google Search, Meta Feed, Email newsletter, Influencer partnerships. It will be tracked in GA4.

Design a UTM naming convention for this campaign that covers utm_source, utm_medium, utm_campaign, and utm_content for every channel listed. For each channel, give me:
1. The exact utm_source and utm_medium values to use (lowercase, hyphenated, no spaces)
2. A utm_campaign value that stays constant across all channels so I can group results
3. A utm_content pattern for distinguishing ad variants or placements within a channel

Existing conventions to respect, if any: We already use lowercase-hyphenated source values like google-search

Then give me a short naming-convention reference table I can save and reuse for the next campaign, plus 2 mistakes to avoid that would fragment my reports.