EVERYONE can invite new members. It's not your duty to invite people. But it does help the guild if you bring active players into the fold.
/guildinvite playername

EVERYONE can promote/demote members of a lower level. Please don't abuse this, it's there so people don't have to wait for me to notice they've leveled.
/guildpromote playername
/guilddemote playername

The guild is split into tiers of trusted players of specific levels. Anyone of the appropriate level without a history of problems is eligble for the tiers.
"Member" Players of level 1-19
"Trusted Twenty" Players of level 20-29
"Trusted Thirty" Players of level 30-39
"Trusted Fourty" Players of level 40

"Trusted Twenty" and up members have access to assign and remove standard bearer status. This is intended to let players share access. If the system doesn't work then I'll revisit it. You can still carry a standard on your person when you aren't a standard bearer, you simply can't deploy it. So, the idea is to assign yourself standard bearer status when you intend on using the standard, and removing it when you're done. If all the slots are taken, it's ok to remove the status of someone who is offline. If all the slots are taken by online players, try your best to share over guild chat. The rule of thumb being that a higher level player has more of a right to the standard. But that's not a concrete rule. Just try not to create any headaches.

To add/remove standard bearer status, right click a player name in the guild roster.

As players are promoted to the higher tiers, permissions are loosened. Click the little gear on the right side of the guild window (next to the rewards tab) to view your tier's permissions.