Jaobler basically said it all. Of course there are always a few more tips some of the members here could contribute.
For one thing you should try Google for coin shows in your area just to make sure you don't overlap with yours.
Check to see if there are any coin clubs nearby that would like to join in.
Make sure there is ample parking and in plain site of the door entrance.
Door prices are not considered against the law in most states so have one or more.
Have a table in the front for flyers for local stores, shops, buisnesses if they want to adverise. Suggest if they do to donate to the coin show.
Make sure your coin shows are more than just once or twice a year. Remember people have short memories but if your show is say the first Sunday of every other month, it should stick in their heads.
You may want to check with the local law inforcement if any of their officers could be on the payroll for security. Always best to have local police involved. Also, if local, they too may have coin collectors in the family. Outside security may just not care.
Always invite me. I may not go but would welcome the invite.

On the serious side you may want to use this forum to get a little help by mentioning your show here.
And don't forget to have flyers saying to check out this coin forum on talbles everywhere since we are helping you. And free too.
If you have complimentary coffee or pop or such, make sure it is either given out by someone or in containers that can not be tampered with. You do not need a lawsuit for contaminated products.
Make sure you advertise the starting and ending time. However, never turn away people if they get there a little early. All the shows by me start at 9AM but I usually get there about 8:30 anyway and no problem.
Try to find someone you know that has a bunch of folding chairs. Many older people need to sit down at the dealers tables. The more chairs at the show, the longer people will stay. I always leave a coin show if I can't find a place to sit. I'm old.
Requrest that any dealers do not go running out early.
Let us know how you do.