All good advice: run the auction for a week - I usually end mine on Sunday's early evening. But check the forum what the best time for your items is. Always depends who your buyers are.
Make sure that you describe very accurately what you are selling, the conditions of the item and the conditions of sale. Cover your butt - there are some buyers out there who love nothing more than to get a freebie.
If the items are really expensive - would you consider other form of payment? I had some negative experience with buyers (thank god there aren't that many) who received the item and the lodged a claim with eBay & Paypal and got the money back. The items were as described and there was no fault with them (I am too honest to be rich
). The buyer ended up with the item AND the money back. It wasn't much but it taught me a lesson.
As you are a seller with little feedback (something I always check) be very diligent with any queries you receive. Make them public so other prospective buyers can see that you are honest.
Make very clear that the shipping costs have to be paid by buyer (if that's your intention) and that any prospective buyer should contact you before bidding about the costs (if it is outside US). Again - some buyers bail after they found out what the shipping costs are.
Do your research on similar items on eBay and other sites. If you have an expensive item buyers will research what they would have to pay for it elsewhere. Not much point trying to sell something that you can get elsewhere cheaper.
Also: include the costs of eBay and PayPal in the price - it's rather expensive and has to be carried by the seller.
Otherwise: good luck