After having decided your course of action, another key factor to remember is to keep scope for flexibility. While in your mind, your idea may be the best logo design ever made, yet the client or product might have some other demands. These may expect you to make certain changes in your action. While it is okay to feel a like your idea better, it is important to remain open to suggestions and incorporate them instead of enforcing your ideas on others especially the client.
The next factor to bear in mind is when you have been tasked to redo an existing logo design or create a logo design for a company that has its own history. In such a situation, there never a compulsion to have the newest and most original logo design each time. If the company has a worthwhile heritage and noteworthy history, then giving full due credit to the company one must be open to recreations as well.
It is essential to never make it an ego clash and simply not consider the work of a predecessor. In case it has something worthwhile that can do justice to the heritage of the brand there is no harm in considering elements of the same.