In order to people trust you, you need a lot of feedback and you can achieve that in 3 ways:
1. the basic way, just sell stuff and it will be growing but it can take a while.
2. buy stuff from your account ( a lot of $1 items) - the more feedback the more money it will cost you (and don't buy 20 items in the same day because ebay will ban you for that, you need to do it smart).
3. ask from people here in the forum to switch feedbacks (search in the forum you will see threads about people that want to do that) - again its very risky because ebay can ban you.
The best way is to mix option 2 with option 1, for the long run just keep selling stuff and you will get more and more feedback.
P.S
After a week that your buyers get their stuff from you, you can send them a message saying that you are new at ebay and you would appreciate if they could leave you 5 star positive feedback.
Good luck