Designing a logo is a great responsibility. It will be the symbol which will be associated with the business for quite a while to come. When you are designing a logo quite often one of the biggest questions is which colour should it be?
Really the number one answer to that is what every looks good to you and seams to portray you in the right light. Whatever appeals to you as the right colour for your logo is probably also the best for the general public. There is no magic colour which gets "more sales".