Which KPIs I should be focusing on per tactic and per funnel stage and are there some KPIs that are more beneficial to look at over others in your estimation?

Complete Question: Which KPIs I should be focusing on per tactic and per funnel stage. Are there some KPIs that are more beneficial to look at over others in your estimation? 

Here's how I like to think about it (after years of struggling with the same question).

1) A KPI needs to be actionable, achievable, and impactful - you'll want the team to be able to say "yes/no" that it's working easily without a lot of hesitation (that's why numbers vs. percentages work so well).

2) The KPI should be widely accepted and standardized. No need to reinvent the wheel. The platforms you use should be pointing you in the direction of the widely accepted KPIs for a tactic.

The simpler and fewer the number of KPIs, the better. For example, I showed how I really only pay attention to 3 numbers right now: Traffic, Email Subscribers/List Size, Revenue.

There are more KPIs I could add, of course, especially if you have a larger team. But these all meet the criteria above quite well.