What can be the most difficult part of a sign design is to have a mutual envision of the final product.  There are factors the client desires and then there is the experience of fabrication and final product delivery that I have. 

Keep it simple.  MAKE IT BRIGHT.

Realize that a sign on the ground and a sign up into the air is like a magic trick.   It shrinks.  The further distance decreases legibility.

What you have to do is start looking at signs.   As you look you will see signs with so much information that you start to read and realize one that you don't have time to fully process the amount of information they are trying to put out ..  and that its like reading a book.. line by line.  You snap your eyes away because you have to stay actively aware of your driving surroundings and attention.

A sign should be one that attracts your attention and with a glance you have all the information that is most important.  Convenience stores all sell the same products.  Liquor stores sell the same products.  Plumbing contractors have the same services.  Restaurants have different ethnic and regional to international cusine.  Look at the major retailers.  Wal-Mart.   Lowes and Home Depot..    You know what they offer.  

Don't make your sign one that you have it so artistic and cluttered with information that a person passing your location starts to read it and their 1.4 seconds ran out before they got the impact your trying to put out there.  AND STILL don't know the name of your business.

Look at signs with script..  you try to read it.. and you cannot even make sense when you finally pull over under the sign and try to read it.  Keep it simple.

LOCATION ..  LOCATION..  Location.   You have the location so take advantage of it.