I'm still tinkering with prices. My sitting fee for events and fund raisers just went up 150%, and may go much higher after the first of the year.
My private sittings are going up 95% as soon as I get my webmaster to make the change for me.
Research into pricing has been difficult. Not many people publish their prices, and the ones that do are all across the board. I finally got another local pet photographer to chat honestly with me. It took calling her up, vice email, and giving her a referral to an event I couldn't cover. Turns out, she can't either, but we talked for a long while and are planning to get together next year for a pow-wow.
On my site, I require a deposit that is non-refundable in the event of a cancellation less than 15 days out. I will apply the deposit towards a new session scheduled within 90 days, but I also require a second deposit to reschedule. Same terms, but only $25.
In reality, I've only had one person reschedule so far due to emergency surgery for one of her dogs. I didn't require a second deposit, and would have refunded the original if she couldn't make it.
I put those harsher terms in writing to fend off those who may not be serious about booking my time.
I second the recommendation to shoot for a rescue (or several) to get a feel for what works and what doesn't in a low-risk situation. I still shoot for 13 different rescues on a regular basis as a volunteer.
There is a bit of quid-pro-quo in that I am the first person they come to for photo fund raisers and private portrait sessions.
Beyond that though, you'll get experience working with various temperaments and personalities (both animal and human) which is invaluable.
It is a great feeling when a rescue animal whose portrait you did for the adoption web page comes by your booth for a portrait with a new family.