Perhaps signature campaigns are a good way, they are not difficult for beginners, and also may help the experienced users.
It's true but there are not many options for low-rank members and nowadays there are not much signature campaigns going on as it used to about a year ago.
You are right about this but you can than first try to get your account to a higher rank, a lot of people did this first and than did campaigns.
Signature campaigns are very profitable if you have the good rank for it and also a good campaign.
Yes the better the rank the better the payout so higher rank is better to be more efficient and have better earnings. Anyways forum campaigns are a great start up for anyone new(er) to bitcoin. Trading is a great way too earn aswell but less great if you are new into the world of investments and bitcoin.
Gambling is fun to do, less profitable though cause eventually you'll lose all. So pick your poison and invest into it.