Negotiating a proper salary is important. Almost all women and underrepresented people get lowballed to start. It is a true reality. So you need to negotiate. 

The best negotiation starts with your first call the the recruiter. You can still negotiation after that, but it gets tougher the further along in the process you go.

While I am great at helping people prepare for the actual interview, I am not the best at negotiating, I still get underpaid, too. I can share my lessons learned, and terrible stories, but if you are looking to negotiate, I highly recommend using the following services: 

Candor

81 Cents

Lenny & Niya