Just piping in because while foodnfoto is 100% correct, and has raised sound considerations, there is a big difference between the high end and low end in food styling and where and how it occurs.
Having an Art Director, Prop Stylist, DP, Gaffer/lighting tech, assistants, set coordinators, editors and multiple producers on set is a reality for certain settings, namely TV & publications we all might know and recognize.
However the rest of the world doesn't often have those luxuries and has to make do without the kind of budgets & schedules that facilitate that kind of high-end effort.
Your day rate as a stylist will vary depending on your market. NYC will command a substantially higher day rate than almost any other market imaginable. There's nothing wrong with starting high, especially if you can reason with your client about the value of that day rate, but in general it's important to consider all other aspects of what is going on financially (which foodnfoto is rightly pointing out to some extent). If you demand a day rate that is higher than your principle shooter/producers/or whoever else that might ultimately be responsible for the vision and/or has the real business need for the shoot, then you might find yourself having issues.
As a photographer in SoCal, not in Hollywood, I start at $450 with my day rate and that's actually a bit higher than many other talented DPs (Dir. of Photog.) I work with.
So, if you demanded $500 (as opposed to suggested for the purpose of negotiation) on one of my shoots you had better well be amazing -- and in general I'm not so concerned with your ability to plate as your ability to see what's wrong and know how to fix it, anticipate what's happening shot to shot, as well as follow my direction without bringing the whole process down to a grinding halt because you need 15 minutes to make a point I already understood the minute you brought it up.
I've worked with professionals who weren't worth the hundreds of dollars we paid for the day, and interns who were worth $1k on the day who didn't get paid anything - it's more like a kitchen that you might think, time is money on a shoot and the value often (not always but often) lies with those who recognize that issue first and foremost and can produce, vs. those who have a ton of creativity to bring that results in a lot of unfinished work of no value to anyone at the end of the day.