From this course I have learned one key element to always keep in mind when making a design is picking the right typeface, when you're making a poster or anything of that matter. It's always good to keep in mind what your client wants and also put your spin on things. Bring a couple idea's to the table but always make sure you do what they want. You want to always make sure the typeface you choose flows with the design that you are choosing.
Also, another elemnt I think would be important that I have learned is something Mr. Sattelmeyer always works into our assingments every week, "readability and legibility." You must always make sure that your piece is readable, meaning is clear and put together with lettering and the way you put them on the design. Legibility meaning the way the design is it's not to much but not to little. Make the design where it's able to be read it's clear and nice.
I think these two elements are the most important because it could make or break the design with the clients and or with the people who see it. I think I have learned first hand that it's not easy doing this all in one design but I also am getting to know myself better with designing and using these elements in my designs.