Well this subject has been answered many times so I'll give it my slant.
You really need to know your market first. By this, I mean you should research the item(s) you wish to sell. There at popular items that will fetch a good price and others that will only waste your time.
Don't just search on Ebay; use other search engines and see what others have that are similar to yours.
You will also need to take good photographs and show all angles and defects,if any.
The third thing to keep in mind, is the wording of your ad. Read many ads of the products you wish to sell and see what others are saying.
Your fourth consideration is shipping.
You need to become familiar with all shipping methods that you will use. I suggest USPS.com and use a digital scale.
Insurance and delivery confirmation are a must.
Paypal is the only payment allowed on Ebay, so open an account,if you are not a member.
Lastly, decide what your return policy is,or not.
This may not be a popular Hub, but maybe the item you are selling is.