What do we mean by a realistic target?
A realistic target is one that can be met with the resources you have available to you. Resources might include time, money or access to other people to help you. The target should also be relevant and useful to you. For example:
Unrealistic: I'm going to read 30 books on astronomy by tomorrow
Realistic: I'm going to read 1 book on astronomy by tomorrow
Making your targets realistic will ensure that you set goals that you have a chance of meeting and will help you work out what resources you'll need to meet your targets.