Here are the mandatory aspects of what a quality objective is:
- You need some to help you meet reg. requirements and product requirements (5.4.1, 7.1)
- They need to be at appropriate functions and levels (5.4.1)
- They need to be measurable and consistent with your policy (5.4.1)
- They get reviewed at management review (5.6.1)
- Personnel must be aware of how they contribute to them (6.2)
- They must must be documented in statement(s) (4.2.1)
- There must be sufficient planning to meet them (5.4.2)
At a fundamental level, therefore, each of these should be some measurable metric. I recommend you make these not one-off metrics if you can - try to make them something that you can measure and compare over a period of time - even a subjective rating is a suitable metric.
At minimum you will want to target regulatory requirements and product requirements. Things like the number of non-conformances in audit might be a reasonable objective. It's OK for objectives to be small and in different places. Try to establish metrics that reward improvement but that don't hold you to an arbitrary line (e.g., an objective to "improve" a number rather than to get some absolute amount).