while not a power seller, we have a side ebay business with over 100 feedback and have been through mostly good but a few ugly sales. i'll point out a few things you should know or think about.
- ebay protection works both ways. it protects the buyer and the seller. as far as who is at fault that depends on the items description and how truthful it was as well as the actual situation but i've found them to be at minimum fair in decisions.
-take good photos! clearly show at least 3 photos of the items. a good set of photos taken against a good backdrop will produce more sales. use a tripod (clarity improves), good lighting (from 3 sides is ideal with diffusers on the lights) and some kind of backdrop (be it cloth, or other.. it should be presentable). do not use cellphone cameras to list.
-do not lie in your ads. clearly point out any known defects. be very descriptive yet concise in your ads. an item described accurately and well will not only sell better but also protects you.
-pack items well enough that a gorilla could not break them. fact: ups uses trained monkeys to deliver packages. the cheapest options to ship are generally via usps (get an account or use ebays discount). for close shipping of heavy items look at regional rate boxes as they could be cheaper. do forward shipping savings onto customers and combine shipping.
-customers like a return policy (generally shipping back is at their expense, some do charge a restocking fee as well). personally we do not however it may garner you more sales to offer one. please note returns based on ebay buyer protection override you having no return policy but it must be proven that the item did not match your description.
-be very careful about listing that an item works, is in perfect condition, is free from defects or other such terms unless you are absolutely sure there is nothing wrong with the item. generally we sell lots of antique items and like using "good condition for its age" as well as "see photos for condition" ourselves.
-if you sell cookware or other items where a user could easily damage a flat surface take a photo with a ruler on top to shop clearly no warp.
-if you are not comfortable with worldwide sales and shipping, set your preferences in options to usa only (exclude all other countries). likewise if the item is large you can have local pick up available but remember you need to meet the buyer face to face (can be local busy public place or your business location depending on your preferences).
-you do not get your money from paypal (well, you cannot access it at least) for 30 days after the sale. this is to let them snag it if they need to force a return. you can only take money out (by default - you can change this as you get bigger) totaling 500 dollars a month. do not keep excessive funds in yoru paypal account and let them get interest on it while giving you zero interest. keep just enough to do business. do also set up a separate bank account to receive payments not linked to your others.
-ebay and paypal fees are calculated separately. you get charged fees on both shipping and the item price. paypal/ebay on item and ebay on shipping. why on shipping? in the past people abused the system by selling cheap with high shipping so ebay did not make its cut. now, all users get forced to deal with this nonsense but you can not blame ebay for it. yes, you still make out on shipping costs despite this. also be careful of listing fees as they creep up on you if you go over your free listings per month though its not much unless you cycle ads for long time periods.
-make sure your prices are lower than everyone elses or, if not that you have better photos, description and quality of item to make a higher price worthwhile. it is a fact that a higher priced item with better photos and description can sell faster than a cheaper item with shoddy description and photos.
-free shipping sells items quicker. yes, you can always bump price up to have shipping paid for by item however when people see free it attracts attention.
-ship items quickly and you will get good feedback and repeat sales. ship them safely and the same is true. combine shipping and the same is true.
-do not make sales of ebay items outside of ebay as they are not covered by protection. only accept paypal if you want buyer seller protection (no cash, cod, check, money order, bank transfer, etc). they can pay with credit through paypal.
to answer your 3 questions concisely:
1. if it's that easy to be scammed, why there are still so many sellers on ebay, even selling luxury items like the new iPhone...
while true that its possible to have issues, as long as you are truthful and careful you are not terribly likely to encounter them. people make tons of money off ebay, and while there are times when things can go sour they could often have been avoided.
2. As a new seller, what I can do to protect myself from being scammed when my goods have no quality problem.
listed some things above but in short: good photos, accurate description.
3. Any more advice for selling on ebay?
invest in a decent camera and use a tripod, set up a good photo taking area, use clear accurate concise descriptions, sell cheaper than others.