Feedback is not used by eBay to measure your account.
Only about 40% of all transactions get any feedback, and I suspect most of that is left by sellers.
I have a new account opened about a year ago which has had 20 sales and only about five feedback left. (It's a slow moving category so the low numbers don't bother me.)
The fastest way to build FB, which is used as a measure of trust by some buyers, is to do some buying.
Stuff you need around the house, or for packaging. Maybe printer ink. And then choose sellers who leave FB on shipment, or at least consistently. Not the guys who withold FB until they receive it.
You might also try Promoted Listings, if newbies are allowed to use it.
This promotion gives you slightly better prominence in Search and you only pay for it if the listing sells.
General opinion is that one percent is enough to get the benefit without paying out all your profits in fees.
Oddly, since I have been using this in my Stores, my sales have increased, but it is not necessarily the PLs that are moving. People seem to see the PLs , consider them, move on and buy something else from me. Which means I get the sale without the PL fee. My kind of price.
