1. Set clear goal and objectives
It all starts with defining what success looks like. What is the task and what do the end results like? What is your expectation in terms of the quality of the work?
One key is, before you delegate, really make sure you as a manager fully understand the entire scope of the project. Preparation is the key - setting aside dedicated time to brief your direct report about the task. And before the meeting, you should take at least a few minutes to thoroughly prepare for it.
Another important point is focus on the results, not the method. It means there's no need to describe exactly how this task should be performed with painstaking details. A variety of approaches could be employed to achieve the same good result. To a degree, the individual approach is the beauty of having diverse talents. Being too prescriptive could run the risk of micro-managing and demotivating.
After setting the objective (what), give your direct report the why - equip him with context and details about the project. The objectives here are two fold. Firstly, helping him understand the rationale will motivate him to perform. Secondly, giving him details around the project, such as what has been done, what has/hasn't worked, could help him accomplish the task more effectively.
3. Align on a Timeline and Regular Check-In Points
It's important to set a realistic deadline for the completion of the task. Meanwhile, if it's a big project with long lead time, set up some regular check-in points to see progress. Outside of those check-in points, try to leave them alone and trust them to progress the project, unless you see things aren't progressing as planned, which led to our last point: follow up.
4. FOLLOW UP
This last step is the biggest lesson I've learned as a new manager. Truth be told, I wasn't doing it right at the beginning. And it's a big mistake. A few things contribute to it.
First, I myself normally don't need a lot of follow-up from managers. I do a fairly good job of staying on track and keeping them updated. Therefore, I'm projecting my work style on my direct report and assume the same. Well, we've all learned situational leadership and know you have to adapt your style to how others perform. If you don't see the results as anticipated, it is your responsibility as a manager to follow up and ask the right questions.
Second of all, it comes down to that strong ownership and accountability: shifting the mindset from "I'm responsible for what I'm personally delivering", to "I'm responsible to what I'm personally delivering, plus what my team is going to deliver." Having that level of accountability is everything. Once you truly take that extreme ownership, it only makes perfect sense that you should feel obligated and empowered to follow up, in the right way.
So these are the four-step approach I've summarized as a new manager. I'm sure as years go by, it will evolve and continue to refine.