Create a plan on what you would like to do. For example, would you like to give out door prizes? Would you like to have an auction? Would you want to serve food and drinks?
Type up a letter explaining what you are doing, and for what. Include a brief description of the organization and/or NKH. Also, pictures are a great thing to add. . Be sure to include what type of donation you are looking for. For example, donations for door prizes, cash donations, auction or raffle item donations, food and drink donations, etc.
Send the letters out or go to local churches, stores, businesses and others that you think might be able to help. I have found that going personally to these places is better. I also took my daughter with me to show what the basic type of person they will be helping, and to answer any questions they may have. Some places will require your signature if they donate anyway.
Send out letters or go to local reception halls, celebration/meeting rooms, or other gathering place where you might be able to have a dance. We had ours at a local bar that had a family room in the back, where kids could go, too. Look for one that will donate their space, or at least do it really cheap. Keep a list of those that donated and list them at the dance to show appreciation and send out Thank You notes as well.
Set up a band or DJ to do the dance. One way to do this is to call the local places like the above and ask them for band or DJ contacts. You could look in papers, or ask around to find someone. Most people will donate their time to do this if they know the cause. Make sure to ask a good time and date for both the place and the DJ or Band to have it. You would want to accommodate both as well as possible for donating.
Decide on price. Talk to the owner/manager of the place you have it at and ask them if they have a standard price they charge, or decide what you would like to charge. For example, would you charge a set cover charge or just have it by donations only. Also, if you are serving food and drinks, what prices are you going to charge?
ADVERTISE!!! I cannot stress this one enough. Advertising is the key. Talk to local radio stations, TV stations, newspapers, businesses, etc about advertising your benefit dance. Make up flyers to advertise and set them up wherever you can. Tell everyone you know and spread the word! The more people that know about it, the better! Be sure to include if there will be any charges, what the rough agenda will be (for example, door prizes given out every hour, auction at a certain time, DJ or band at a certain time, food and drinks at a certain time, etc.), and what it is for, with a brief description of the organization or disorder, as you did for the letters sent to get donations. You may also want to put a list of donated items, if you wish.