Choosing your target needs to be a considered balance between the right amount you need to make your project happen, and what you can realistically raise from your crowd.
Choosing the right - or wrong - target can make or break a crowdfunding campaign. Setting an overly ambitious target may see you fall short if you don't have the crowd to back you up. On the other hand, you need to make sure you have at least the minimum funds available to deliver your project as described.
On the whole it's better to err on the side of caution. You can always make sure you enable Overfunding and then you have the possibility to put the essentials in your main project budget, and the 'nice-to-haves' in the Overfunding section. Read more about Overfunding here.
Another important consideration is having an awareness of the size of your crowd and the potential money that exists within it. Understanding this may tell you that you're aiming too high, or possibly too low. We have a very useful crowd calculator which helps you to break down your backers depending on who they are, how much they might pledge, and how likely this is. You can find out more about how to use this here.
Remember, you do not set a 'target' so to speak. Your target is made up of all the different cost items that you list as part of your project budget, plus the fees should you run a successful campaign.