Inactive Members:
Some people don't care if they have frozen members or people who haven't been on in month in their guild simply because it makes the member count higher. I'm here to tell you, although you may want tons and tons of members, guildless people might think they'd get overlooked, when in reality, there's only about twenty active members. So, I strongly advise you to make a rule that at the beginning of every month, people who haven't been on all month long (unless they've Neomailed you about it) will be deleted. This causes many advantages. 1, it will be easier to gain members. 2, all the members of your guild will be active. Lastly, 3, it keeps the guild circulating.

Bashes, Activities, and the Like:
Members will eventually get bored if you have the same old activities again and again. Try to encourage members to host activities that hold creativity. There are two basic type of people who participate in activities: 1. The ones who do it just for the prize and 2. The ones who are artistic or love challenges and trying to compete with others. If you have teams, rearrange them every two months or so, that way people can meet new people. Bashes ARE against Neopets rules, and it is completely and utterly your decision to hold one. However, they are a great way to get everyone active! The rarer a bash is, the better they are. Advice! Don't hold weekly bashes! Try and only hold them for Holidays: Christmas, Halloween, Thanksgiving (not suggested since not everyone lives in the US), and Valentines Day. Also, you could hold one every time a major goal has been reached (i.e. 100 members).

Council and Ranks:
The more members you get, the harder it probably is to keep on top of everything. DO NOT, and I repeat, DO NOT have a set time for when you're going to pick council positions (i.e. "Council position IV chosen at 100 members!"). It is much better to just choose when you actually need the help. Also, when you're choosing someone, do not base it on how cool or liked they are. Base it on how well they could help you with the guild. Now, with rank upgrades for members, you may want to make the requirements more difficult if too many members start advancing to the top. It's supposed to keep them active and competitive, and once everyone is pretty much the highest rank, it gets boring.

Misc. Things:
One thing you need to be aware about is Donation Shops. They ARE against Neopets rules and people do frequently get frozen for them. It also causes much drama if your guild ever dies, so I suggest you keep an exact list of who has donated what so you can give as much as possible back to them if the guild is deleted. Do not plaster all over your layout, "Donate now!" for the simple reason that it makes you seem greedy and untrustworthy. Do not make it a rank upgrade requirement to donate. If you have dedicated members, chances are they will donate on their own. It's actually almost factual that if you don't push people to donate, they will.

Something Big:
Do something spontaneous and big. The hot thing going around right now are Guild Plots. So many users enjoy Neopets plots, and if you have a Guild one, it gets members active and participative! Make it hard (but not too hard!) and suspenseful. Give some comic relief and include members in the plot's story. This is proving to be a very successful help in guilds right now. If you don't have the creative juices to design a plot, that's still okay! Do something else that's big and exciting. Your number one priority should be to keep members entertained!

There are many other things I could tell you to do, but you need to have faith in your guild and just think of everything from a member's point of view. Don't give up if some members quit your guild, and don't look like a clone of every other "it!" guild out there. Be creative and imaganitive! In the end, that's really what people are looking for.