You need to sit down and calculate all of your costs over a year include equipment depreciation, car running costs, insurances, office costs (stationary etc), computer equipment depreciation, internet costs, phone costs, marketing etc (there is probably more but I'm tired) then you add what you would expect back as a personal salary $60k for example. Add all of those up and divide them by 100, which would be the approximate amount of days you would actually be shooting (the rest is marketing and chasing business). This should give you a day rate that you would expect to get to run your business full time.
Lets say it all comes to $130k inc salary, divide that by 100 and you get $1300 per day (you can divide that down by 8 hours if you like, but set a minimum to allow for travel time and set up, i.e 3 hours min is what I use.
Now on top of this for each quote you need to add any extras, like assistant cost, printing and time for editing.
Now a lot of you think that sounds steep, but the reality is that after all of the costs a return of $60k is not an over the top salary. And now you know why full time pro's get so upset about part timers (I am not going to call people amateurs) charge only a couple of hundred per day, or even do it for free to get into the industry. The problem is that if you ever do make it into the industry full time, the pricing has been driven down so much you will never survive. I hope this helps.
Mick Brown
Disclaimer: You may already be charging fair rates and doing very well for yourselves, this post was not directed to anyone in particular but to inform all of how a photographers rates are derived.