Join a signature campaign when your account goes to full member or upwards. But do not spam, you'll get banned and that's not worth it. Make constructive posts only and you'll benefit from the forum.
Thats right you can earn bitcoin through joining signature campaign especially when you have a high rank acount but if you decided to begin in the first place then you must rank up your account to have a bigger profit in joining signature campaigns just remember not to spam.
This is the only better way to earn Bitcoin through joining signature campaign because it's free to join depending also on your rank in the forum. Better to check also your account first before joining signature campaign, if you have a good quality posts automatically you be hired in the campaign. Avoid also spamming with a short reply like thank you,ok, I like that, +1 and whatsoever.