As a ebay member you should expect to be targetted by hackers. Most usual way is through bogus emails which looks like they are from ebay but in fact they are not. Some hackers can even program as good that the messages seems to be received from ebay's servers and return address is a genuion ebay email address but they are not from ebay.
Most commonly in these emails you'll be either get a threat like your account is suspended , some has opened a dispute against you and so on.
The very first thing you can find out if it is a fake email is it will not contain your name. All original ebay emails starts from [eBay sent this message to Your Name (your ebay id)]. Fake emails will start with same line but instead of your name it will only say [ebay sent this message to You]. They will not have you name in it. But still you have to be very conscious there. If your email address is part of a mailing list of hackers it will not have you name, but if some one is personally trying to break in to your ebay account you may find your name and ebay id in email.
The purpose of these emails is to make you surprise and force you to quickly act upon them. They will all have link for you to log in to your ebay account. But in fact when you click such a button in email it takes you to a site which looks same as ebay but it's not ebay's web site. Once you enter your ebay id and password the hackers will have these details open to them which they can use to log in to your account and do what ever they want.
How To Avoid?
Most of the time you'll know straight away that email is bogus because it doesn't contain your name and ebay id.
Make your habit not to act upon emails even if they are from ebay. Always open a new browser window and go to ebay website. Log In, you will find any task need your action.
When some body asks question about your item, if you are replying using your email software/website, it will contain original email in reply which has your name in it. Delete this part of message or better you open ebay website in new browser window and use ebay's message service to reply.
Set your email servers security bit higher for spam, but always keep an eye on your spam email folder as it will some times catch some original and necessary emails.