OKRs are a management and alignment methodology made famous by Google. 

The Objective is qualitative, and the KR’s (most often three) are quantitative.

They are used to focus a group or individual around a bold goal. The objective sets a goal for a set period of time,...

OKRs aren’t just about hitting targets but about learning what you are really capable of. When missing a KR you've learned a ton about what works and what doesn't. 

Much of the value in OKRs comes from the conversations on what matters, how it will be measured and what it means for the teams who are used to working from their own standards, apart from the business goals.

Individual OKRs are about

Your objective defined in a single sentence should be:

• Qualitative and inspirational. The objective is designed to get people jumping out of bed in the morning with excitement.
• Time-bound. You want it to be a clear sprint toward a goal, doable ...

Key results take all that inspirational language and quantifies it.

You create them by asking a simple question “how would we know if we met our objective?”

Often people fail ...

...because they set OKRs at the beginning of the quarter, and then forget about them until the end of the quarter.