There's lots of advice about Ranthambhore but some bits are still quite lacking especially when it comes to the safaris themselves.
Some things I'll go through here, but I won't have answers to some of my questions (where is the departure point for safaris, how do you actually get from your hotel to the departure point, which is the nearest hotel to the departure point) until I return.
Types Of Safari
There are two safaris per day, one very early in the morning - mine start at 5:30am! - and one mid-afternoon - mine start at 2:30pm.
You can book on either a 'Gypsy' (6 seats, + driver + guide, petrol) or a 'Canter' (20 seats + driver + guide, diesel).
For more information there's a very good thread on IndiaMike that I've been involved with named Ranthambor Info: Jeeps, Canters and all that jazz. Read this, you'll learn loads.
Pictures of a Gypsy and a Canter:
Booking
Everyone advises that you should book your safari direct on the Government of Rajasthan Department of Forest web site using the Ranthambhore Online Bookings page. Booking is available for dates 90 days in advance, but just like trains, but unlike flights, there's no point in waiting as the price never gets better. So, as with trains, if you know when you're going to be at Ranthambhore you might as well book up.
At the time of writing the prices are as follows for a foreign national like me: Canter:Rs547 Gypsy:Rs64, about £8.5 and £10 respectively.
So you're talking about Rs100 (£1.50 ish) extra per safari for the benefit of only 6 people in the same vehicle. It's no contest, why would you even consider a Canter is a Gypsy is available? Coupled with the fact that the canters are diesel.
Paying For The Booking
Booking the safaris isn't much trouble: go to the site, select the date, enter the number of morning and/or evening places you want, fill-in the details about each person, including names and passport numbers and then proceed to pay for it all.
It gets interesting when you have to enter your credit card details.
You enter all of your info and credit card details and then (I'm guessing) the site realises it can't handle your international credit card and forwards you to payment gateway number 2.
Again, you enter all of your info and credit card details and then (I'm
guessing) the site realises it can't handle you international credit
card and forwards you to PayPal.
You log in to Paypal and pay and the booking is made.
Throughout this process you're never informed that you're being redirected due to your international credit card and more importantly you never get the chance to say 'Hey, I've got an internation credit card please take me straight to Paypal.
NOTE: I've read that others have had trouble trying to pay via Paypal when their Paypal account only has a credit card attached and no bank account. For me this wasn't a problem as my Paypal payments come straight out of my bank account.
Timing
As I said earlier, just book it up, why wait?
The proof is in the pudding for me: I booked as soon as I could and got just what I wanted. Today, one month on 40% of the seats have gone.
Obviously if the spaces for a Gypsy sell out you can probably always get a ride in a Canter, but with loads of others, in a diesel, trying to spot wildlife, no thanks.