Here's what's worked for me.
Do your homework ahead of time. What do you need vs what can you live without. IE: I don't care about built in Nav as I use my phone so a car with Carplay is more important to me than Nav. Act like you know exactly what you want when you walk in. Heck, you can even start with "I saw on your website you have a blah blah model, this color and this trim.. here's the stock #, what's your best price..."
Shop between Xmas and NY, the absolute best time as everyone wants to meet their quota for the end of the year.
Don't be afraid to walk away. Probably the most important advice. The salesperson and manager will make it seem like you are getting the best deal ever - you aren't. Take their info and go to another dealer and say - can you do better than this
Start with the overall price and negotiate that down.
Do you have a trade-in, don't tell them. Overall price is key. Negotiate trade in after or sell privately or get a price from Carmax first and have that ready for the final part of the negotiation.
Check this lady out
https://www.cowartautoconsulting.com/
I catch her tiktoks now and then, she's got some amazing advice and personally, I could listen to her drawl all day.
That is what has worked for me, others will have different (probably better) advice, some will say CJ's voice is awful and then folks will start to get political and defend Ford or Dodge an the troll will weigh in with his stupidity.
Good luck!