Now some of these may already be in effect, if so over look that one.. Here are a few ideas to make the server better.
1. Rules : Need to be posted, and also clear enough for all to understand. That way they can't pull the "I didn't know" crap that most try to pull
Rules Examples:
1. No discarding items in the towns period. (Lag Issue)
2. If your caught hacking (Speed, Packet Editing, Dupping, ect.) You will be banned without warning.
3. Don't hang around or go AFK around town NPCs, it causes lag for players that need the NPC for whatever reason.
4. No Flamming
5. Follow Chain Of Command for GM/Admin (This is mainly for Server Owner) It keeps him from getting overloaded with players complaining about GMs.
I would have other rules that are just for GM, but you may have already set them, and since I am not sure on the structure of the GM/Admin here, I will not post any.
These are just a few that most would say are common sense, and I would agree, but when someone gets caught doing something they are not suppose to be doing, you will always see them play dumb.
I would not change any of the rates, and keep things pretty much the way they are. I would do a stress test to see how many people the server can hold, then adjust the player cap to try and prevent lag.
So these are my ideas, and I hope they give some ideas that you can use to make it better for all (Including yourself, the less work fixing you have, the better it is.. )