What to negotiate with the builder?

Just about to build for the first time and am pretty close to choosing my builder and home design. I was speaking to the sales lady and she says to me

“when you are ready to sign the contract, that’s when we negotiate. You have a think about what you want to ask for”

however I have no idea what I should be negotiating/asking for.

I am currently at $360k for the build and know that there is a fairly extensive list of additions (extra downlights and power points, drawers instead of cupboards in kitchen and bathrooms, upgrade the kitchen appliances, built in study, drawers etc in wardrobes... the list goes on) which I suspect will add up to 10-15k

Any thoughts on what I should be negotiating on??
TIA

It's really hard to tell without knowing exactly how much room they have to play with.

A common one is negotiating a fence or some landscaping into the quote for cheaper then you know it'd cost you after. When I did mine, at the last minute we ended up with two civility sliders, tiling to the front porch and a coloured driveway, plus fencing without any builders margin added. It wasn't much but I was happy with the price I paid.

To be honest, it's easier negotiating over land if it's not selling quickly. Can normally take a few thousand off there.