Negotiation is uncomfortable, which is exactly why it works for people who do it.
Do your homework before the number
Know the band for the role, the company, and the city. A number without a benchmark is a guess, and guesses lose.
Let them go first
If you can, let the company state a number. If you must answer first, give a range anchored to research, not to your current salary.
Negotiate the package, not the salary
Base pay is one lever. There is also sign-on, equity, holiday, remote flexibility, and start date. When base is capped, trade there.
Stay warm
The tone matters as much as the number. You are negotiating with people you will work with. Be direct and friendly.