As a NEWBIE, my suggestion is to post high quality posts to improve my rating, otherwise there are very few rewards campaigns that allow NEWBIE to participate. Most of the minimum bounty requirements are Jr.members.
In many bounty campaigns minimum rank is member. With more people
we have more campaigns that asks for more, not just higher rank now
many campaigns asks for members with a lot of merit's.
I will give one more suggestion, social networks. As you are building your
rank here, try to be active on social networks. Having more friends/followers
can be very profitable this days. There are many social network bounties, some
of them pays more for this campaigns than for signatures.