A common question I hear from managers is "how much feedback should I give?" I usually give a fairly easy answer (as much as you possibly can), but realize that the issue is a little more complex than that. More importantly - there is no "correct" answer.
Because feedback is dependent on observable behaviors, you are limited in that regard. You can't give feedback unless you see something. As you progress as a manager, you will start to see more and more through experience.
Yet, you shouldn't give feedback to everything you see. Then the feedback loses its impact and becomes too much.
My suggestions focus on 2 key areas: Feedback Ratio and Total Feedback.
Feedback ratio is simple: the employee's performance will dictate the ratio. A players should get 90% positive. B players 80%, C players 70% and everyone else gets at least 60%. Notice that your weakest performer still gets more positive than negative feedback.
Total feedback isn't nearly as precise and depends on the situation. I think the minimum is that each employee should get at least 1 piece of feedback a week. I think the maximum is 1 piece of feedback per day. However, team size matters as well. If you have a team of 10 people, it may be possible to give 10 pieces of feedback (1 per person) per day. It may be more reasonable, particularly when just starting, to give only 4 or 5 pieces of feedback per day.
My suggestion is to select a number you are comfortable with to start, then adjust as needed - keeping the minimum and maximum numbers in mind. Periodically, review how you are doing and adjust your feedback quantity goal as needed.