The following are some basic tips for buying and selling of personal goods only and not commercial products as sale for business, using personal experiance.

Tips for Buyers :

1. Verify the product:
   Take for example, an mp2 player.There are many products which are not branded but look similar to other branded products.There are mp3 players that look like apple ipods but are ot at all related to each other. Make sure of what you are buying by asking the seller about the product.
   
   
2. Check seller Performance:
   The performance of every seller is listed in any trading site. Just merely do not see the percentage.You will not be able to read the full review as it may be too long. So read all the bad reviews.Read the first Ten good reviews to understand the seller. Importantly, read the review of what the other buyers have to say for the similar product that you are going to buy.If there are no review on the product,do not buy. If the seller is selling only one piece of a product, you may not find reviews on that product so read about the other reviews atleast.
   
   
3. Ask seller any doubts you have:
   Do not hesitate to ask any doubts. If seller does not reply and the time is ending soon, do not buy the product.
   
   
4. Keep a record of your conversations :
   Your conversations will usually be recorded by the site. You can use the to refer any promises or guarantees made by the seller during clarifying doubts.
   
   
5. Bid only if you are interested :
   Do not participate for fun as it would result in bad reputation.
   
   
6. Always keep the record of the referance number of product purchased for future referance.Enter the referance while payment if seller does not prescribe any method.
   
   
7. Keep record of your payment.
   If the seller does not respond after the prescribedtime, contact the trading site.
8. Always post comments whether good or bad on the seller after completing the trade.

Tips for sellers:

1. Be sure of sale:
   Be sure that you want to sell a particular product. Otherwise,withdrawing a product during auction would lead to bad reputation.
   
   
2. Be HONEST :
   If the product becomes damaged during the sale period, post comment so that buyers don't buy it. If this occurs after sale, inform the buyer .
   
   
3. Advertise in right category:
   You must advertise the product in right category. Even if it is a 100% new book that you have not opened, but had it for 3 months in the shelf, it becomes a used book and you should place them in 'used' category.
   
   
4. Proper Organisation :
   Enquire the transport details in hand, so that there will not be any delay while sending the product.
   
   
5. Know the buyer :
   You have to read the reviews of buyer as they would read reviews of you. Check if the buyer makes prompt payment, by contacting the previous sellers.
6. Keep a record :
   Keep a record of courier bills as they are the important sourece to show if buyer has not recieved the product.

Hope these basic tips help you out. Happy Trading !