Advice regarding designing business sign

Mack34

Hi all
Hope you are fine
My friend started a new spare parts shop in our locality, and it becomes successful within a few weeks. Now he plans to elaborate the shop be availing more products and increasing the shop's outer look. We plan to install a signboard and an advertising banner to attract more customers. The signboard help to identify the shop very easily. To design a unique sign for our business is not an easy job.
What all care to be taken while designing a business sign to be unique? It will be ideal if you talk about your intuition with us all.
Thanks!