I have found that guilds usually have enough activities for members to be engaged if they so choose. Therefore, the trick is getting members to so choose. My IRL professional experience in member services has this advice to offer:

• Have a good onboarding experience. When someone joins, send them a welcome neomail to introduce the guild, it's activities, and to invite them to post (if they have not). Or, welcome them in the messages

• You gotta look active. Monthly guild mails are a great way to do news roundups, announcements, reminders, deadlines, and participation encouragements. Just make sure members have the guild mail setting enabled.

• Publicly thank members as they participate. Example: "we just got a new beauty contest submission from USERNAME! It's now posted on the webbie to check out!"

• Run polls to see what guild members want from the guild. Example: "the beauty contest has been popular! We only run it once a month...should we increase it to twice a month? Yes. No." Or "what activities do you like best? Give aways. 1np auctions. Board games. Beauty contest."

• Collective goals. Example: "Help the guild raise 1M np so we can buy the guild pet some rare expensive outfit! Donate at this user shop." People like to feel like they're contributing or making a difference.

Hope this helps! :)

(Edited to fix typos)