Creating a Joomla!Day requires a combination of good leadership, teamwork, and lots of energy. A successful Joomla!Day isn't measured solely on the number of attendees, but rather the value of the information shared and the new connections made within the local community. This is a simple guide that Joomla!Day organizers can use in creating their own Joomla!Days. Even better, this page should be used by past Joomla!Day organizers to share their knowledge. The more information the better!
The best way to start is building a small team. This team should meet regularly and the members of the team should be informed about all the things that are going on. Keep this team small, 3 or 4 people are a good size, if you have more than that, finding a meeting time will become more complicated and the meetings will take more time and become less focused.
Assign individual tasks. Nobody should have the weight of the entire event on their shoulders. Spreading the tasks out to others in the team will make everything easier in the end and promotes accountability within the team.
Document what you have discussed in the meetings, an easy way is to do that is within the meeting with a shared document. Google docs is quite good for that. Documenting the meeting minutes immediately after the meeting will ensure accuracy and accountability.
Start small with your event, you can extend it later but it is easier to extend then to reduce the size later.
To make an official Joomla!Day you have to follow some rules. This can be quite simple or complicated depending on your decisions.
The first thing you should do when you consider organizing a Joomla!Day event is to read the Joomla!Day Charter at this link: 
If you know the date and the city you will make your Joomla!day you should send in your request for a Joomla!day. You can do that over a simple form at the OSM Website
When you make your first Joomla!Day you normally don't have a domain you can use for the Joomla!Day website. Something like joomladay followed by your top level domain is a good choice e.g joomladay.de or joomladay.nl. It is not the best idea to add the year or something else to the domain name, because you can not reuse the domain next year and you have to go to the approval process again. So keep it simple! It is necessary that you have a running website at the domain you'll use. If you don't have the website but some mockups or graphics then you should make this available. Here is the link to the domain request form
The easy way is to use the conditional Joomla!Day Logos, you can use them without any approval process. If you like to use the Joomla! logo you have to send in a logo usage request and go thru that process. It is strongly recommended to use the conditional logos.
Don't forget to include prominent and appropriate places in your site for your sponsors
The city where the event shall be should be easy to reach for the targeted audience. Public transportation should be available to the city and to the venue. There should also be enough hotels (check prices!).
Larger cities offer better infrastructure, but mostly the venues are more expensive. Don't forget to check smaller cities with good infrastructure.
The final decision for the city should be made together with the venue.
Before choosing the venue, some key facts should be planned:
There are a lot of different types of venues possible: conference hotels, companies, university, ... All of them have advantages and disadvantages. A venue at a university can be very cheap - but normally, you have to care for everything on your own (technical equipment, catering, cleaning, ...) while conference hotels offer full service, but are most expensive.
When you compare the prices for the venues, don't forget to include the technical equipment (Projector/Beamer, WiFi, Whiteboards, Sound, ...). If this is not included, this may be expensive to rent.
Check the following dates:
There should be at least 2 weeks between other similar events.
The event should be planned at least (!) 6 - 8 months in advance!
Lecture, breakout rooms, and unconference modes.
Where possible you should aim to have local speakers. Having international speakers can be a great attraction for your event but try to avoid having too many speakers who are not presenting in the native language of the JoomlaDay.
When you try to find sponsors, don't forget that you are dealing with companies. They expect professional and reliable information and agreements.
Before contacting sponsors, prepare
Giving away donated goods and services at the end of the day can be a very slow and boring process. Joseph LeBlanc created a Joomla extension that will make the whole process much faster and less painful http://extensions.joomla.org/extensions/miscellaneous/15024
"This component allows you to award giveaways at random to the attendees of a JoomlaDay. There are mass import functions for attendees and giveaways, as well as a CSV export feature for downloading the final results. Winners can also be displayed on the frontend of the website."