I can't - I have been on ebay for aprox 10 years and sell and buy for fun - I don't make 'GOOD MONEY" on it. I don't think very many do - it is a garage sale venue for most people - but you can pick up a little extra cash if you are lucky and find the right items to list - but you need to know about them ie antiques, kids clothes, books, etc. You will only lose money if you try to drop ship new items - a zillion other people are trying to do that at the same time you are - it is the same ol story
It dosnt matter what your "products" are you will still need to :
1. buy some stuf on ebay that you will need when you start selling - digital scale, bubble wrap, mailing envelopes, etc
2. buy some stuf you can use anyway - clothes, books, etc
3. build up at least 25 f/b then start to list stuf you already have - books you are done with, clolthes, etc.
but be sure to check what the EXACT same item has been selling for
4. check the requirements for selling - such as clothes have to be washed unless they are NEW and NEVER worn. etc.
5. check the cost of mailing each item so you won't get stuck with quoting the wrong price.
6. list 8 or 10 things and see how they go -
7. don't start with anylisting over $10 - less if you can
8. after you have 100 or so f/b you can start to list higher priced items.