Once you have submitted your work, it's often tempting to forget all about it and move on to your next assignment. But at some point your work will be assessed in some way, and it's important to understand this assessment and any other feedback you might receive.
A short simple essay may simply be graded and you may receive a few helpful comments or suggestions. If you are lucky, you may receive a grading rubric which will help you identify strengths and weaknesses. You should read this very carefully; it will help you improve your future assignments - it's all part of the learning process. You can read more about rubrics on the rubrics page.
A longer piece of work will merit more extensive feedback, with a more detailed rubric, lengthier comments and perhaps the opportunity of discussing your work with the assessor or assessors. If you receive written feedback before this discussion, make sure you read it carefully before the interview so that you can raise any issues you do not understand, and save time (yours and the assessor's).
Feedback is more important than any grade so you should welcome the opportunity to discuss your work with your assessor. If you feel nervous about discussing your work, it's very useful to discuss it with a friend or colleague before you even submit it. This is all part of the iterative writing process. Conducting any kind of peer review is useful for identifying errors, picking up ideas about how to improve your work, and helping you to stay relaxed about discussing your work with others. You should be told how your work will be assessed and an assessment rubric may (should!) be available to you for any assessed task. If it is, you should use it to assess your own work and possibly that of your peers before you submit. This helps you and your peers to make sure that you have addressed all aspects of the task, and to understand how your work will be assessed. Any subsequent discussion with your assessors will then be much more focused and fruitful. You can read more about understanding the task on the understanding the task page.
If your work is published (for anyone interested to see), then you may receive all kinds of feedback - both gratifying and much less so. You have to learn to cope with unsolicited negative comments about your work.