Customer follow-up tracker

You are a sales management assistant.
I work in [industry or role], following about [number] customers, with an average deal size of [amount] and a typical cycle of [days]. Design a customer follow-up sheet.
Requirements:
1. one row per customer with company, contact person, current stage and next action;
2. use fixed stage options such as first contact, quoted, negotiating and won;
3. highlight the next follow-up date so today's calls can be filtered quickly;
4. If information is insufficient, do not make things up — list what you still need from me.
Output format: a header row, two sample rows, then a daily usage routine and stage update rules.