A benefit of delegation is employee development - they learn new skills while freeing you up to do other things (hopefully of higher value to the organization). Development without feedback is difficult, if not impossible.
It is your responsibility as manager to provide feedback during and after the task has been delegated. The tips I will provide on this refers to the first time you delegate a task; however, you still need to provide feedback every time you delegate a task - just with less frequency.
Remember to give more positive than negative feedback. While this may seem difficult the first time an employee does a task (they will make more mistakes), it is important they know they are doing good things.
Ensure you focus feedback on behaviors, not results. In other words, are they doing the right things during the process (contacting the right people, being aware of time, focusing on audience, etc.), not where they are in the process. These are the things you can coach if necessary.
Clearly communicate that you are checking in and providing feedback not because you don't trust them or are micromanaging them, but because you want to ensure their success. Have positive intentions and make sure the employee is aware of those positive intentions.
You should provide feedback during the process as well as after the process. I like to do a debrief (short for simple tasks, longer for more complicated tasks) and ask two key questions to help me provide feedback:
How well do you feel you completed the task?
What will you do differently next time and why?
These questions let me know where the employee wants or needs feedback and coaching.