Well basically you want to start with your own niche so don't try and explore a oversaturated market.. ie don't try with anything branded as you can't source it legally and it won't be genuine original stock (if buying from china).
Start small and follow these steps,
Source niche Products for non- over-saturated market
account for all fees
COGS (cost of goods)+shipping+eBay fees+payment (paypal fees)+#30-40% market for profit depending on how greedy you are.
*I can't stress enough you must have a like towards the products you aim to sell otherwise you will just get bored. If you share a general interest you will self motivate yourself to achieve higher goals and improve productivity and results.
Buy some sample stock less then #5 pc/s if possible to check your supplier and the quality of the goods.
List on eBay
Using auctiva / inkfrog/ listing creator if you want to make it nice and professional looking.
Use proper photos nothing with overexposure (white flashes)
don't put a %60 markup unless you know you can get it,
Factor in shipping, listing fees, paypal fees...
If accepting payment via paypal you MUST Post via Registered Tracking in the event the item is lost this is the only insurance policy which paypal will accept.
I'm not going to tell you what to buy because I'm selfish and don't give out ideas.. find your own niche sector and make your gold.
Hope this helps a tiny bit.
oh and ps. (Do Not buy Branded Products from China)
Start with something unbranded and generic so you don't run into legal problems with eBay's VERO (Verified Rights Owner) team and take small little steps to achieve your goals.