Getting the site right will ensure the success of your project. Make sure the panel is accessible and easy to read preferably from somewhere with hardstanding. Not many people want to stand in a muddy puddle!
If possible site it somewhere with enough space around it so people aren't in the way of other passer-bys if they stop to read it. If it does have to be sited behind a fence or similar then let the designer know so they can make sure the text will be readable.
If it is under a tree then the panel will need regular cleaning. If it is in direct sunlight then the panel may fade in a few years.
Planning and landowners
Once you have chosen your site, you must check with the land owners and your local planning authority. If you need planning permission then allow the money and time for the whole process.