Starting a regular raiding schedule
Picking raiding days is hard. They need to be set in stone and regular so people can organise themselves around it and you can advertise them during recruiting times.
If you are at the point of starting to pick some set raiding times, you are NOT going to be able to please everyone, so don't bother trying. In short, you need to set the raiding schedule based on when the most people can show and also when your Raid Leader and MTs can turn up. Everyone also needs to understand that in this case by sheer practicality it is GOING to be majority rules. If 10 people can turn up on a Thursday, but only 6 can turn up on Monday... and you can make Monday but not Thursday I can tell you RIGHT NOW that 10 man raid will run on Thursday and it is not your fault and it is not the officers fault.
Raids will run when people can make it - that is not the officers fault, so be nice to them.
Rotating rosters are fail and confusing. Don't even consider a rotating roster. Keep your weekly raids regular and people will make them because they know what to expect.
Not everyone will be happy with the outcome, but hopefully most people will.
Use a calendar, either in game or php raid calendar or something similar on your website to advertise the raiding roster and get people to sign up based on that.
Adding but not subtracting
Once you have a raiding schedule it is trivial to add in extra runs. What is not so trivial is moving or removing raids. As soon as you move something you will start Guild Dramaz, and this is something you really dont need. If moving a raid night becomes a necessity, it needs to be advertised in advance and good solid reasons given as to why (because people that cannot make the new night will feel that they are being singled out and persecuted, even if that is not the case).
The importance of communication
Getting solid consistent raiding running is based on communication. Officers need to communicate raid plans and schedules as far in advance of their raid as they possibly can and the guildies NEED to communicate when they can and cant make it and when things change at the last minute. There is NOTHING more annoying than having 8 people turn up to a raid and 11 people said they would be there and then the raid wont run. Often people rearrange Real Life to raid. So be courteous and help work out a regular raiding schedule that works for the guild.
Officers should have as many ways of contacting raiders as they can OUT of game. This often includes SMS, guild websites (inc raid calendars and PMs), emails, phone, chat clients (like MSN) and vent/teamspeak servers. Guild members should have out of game contacts for their section leaders and raid leaders so that if something comes up at the last minute (OH NOES THE CAT ATE MY CAT5 CABLE!) they can let the officers know that they wont be there and the officers can find a replacement.
It all comes down to respect. Respect your guildies enough to keep them informed and respect your officers enough to let them know when your circumstances change.
WoW is a team sport, don't let your team down but not communicating effectively.