Rebranding talk

So I am thinking of doing a company rebrand. We are still a startup and very small, but our industry focus has shifted over the past year to 18 months since launched.

What are some things to take into consideration when doing a company rebrand and any advice how to get started?

Also any tools that you may have used or know about that made your branding/rebranding process smoother.

Further what are some things to avoid, mistakes that were made and precautions to take.

Cheers!