In addition to the advice you have already been given, there are a couple of other options to use to improve your chances of getting a decent price for the item.
Once you have finished researching the prices that similar items have sold for and have decided on a price you need to choose how to list the item. If you're listing the item using the Auction format then set the listing up so that you'll still end up with the bare minimum that you want for the item once eBay and PayPal have taken their cut of the selling price, even if you only get one bid. If the item ends up attracting a lot of interest and you receive a lot of bids for it then it could end up selling for more money than you expected.
Should you decide to use the Buy It Now format use the same method as described in the previous paragraph to determine the Buy It Now Price. If, however, you choose to list the item using the Buy It Now format but also decide to include the Best Offer function then you need to alter your tactics slightly so as to be sure of achieving a decent selling price. Set the Buy It Now price up so that it's actually quite a bit higher than the amount that you were originally going to ask for. Once you have done that set up the Best Offer option to automatically accept offers equal to, or higher than, the minimum amount that you want for the item, the bare minimum being the price that you would otherwise have put as the Buy It Now price. When you've done that set the Best Offer option up to automatically reject offers that are 1p less than the lowest price you chose to automatically accept. By doing this there is no "grey area" in between the highest amount to reject and the lowest amount to accept. If you did leave a grey area in between the two amounts then you would have to review any offers manually that fell into that grey area and decide whether to accept, counteroffer, reject or ignore the offers. However, by setting up the Automatically Accept and Automatically Reject functions up as I described earlier you wouldn't even have to bother with considering offers manually and trying to make your mind up as to whether or not to accept the offer, as the offers would be accepted or rejected automatically based on the pre-programmed limits that you'd set when preparing the listing.
If you do decide to set up a Buy It Now listing and you set the advert up in the manner described in the previous paragraph then any ridiculous offers would be automatically rejected on your behalf, whereas if somebody made an acceptable Best Offer or committed to purchasing the item using the Buy It Now function the listing would end straightaway and the buyer would receive a prompt from eBay to make payment for the item.
