Yes, there is an option of booking via Tatkaal system which will be extra cost than normal booking ticket fare and its extra cost depends on train, class and route etc. you can book 3 days before to start date of your journey. Try to book it online early morning or stand queue at the railway counter in the early morning to get it, there is a possibility of getting ticket if you book via Tatkaal scheme 3 days before journey – otherwise sometime some route hard to get it by Tatkaal system even you try to book 1 or 2 days before to journey’s start date.
In normal booking, if you get RAC 3 days before to start date of journey, kindly buy it which can come to confirm status upon journey date and you can see your name on the booking chart also you can re-confirm PNR via your mobile few hours before to start journey.
If you have still problem, then you need to book the ticket in 1 month or more advance as only some routes very hard to get it confirm ticket within few days/weeks.
This is really pathetic while travelling in train without reservation for long routes. As you have no seat to sit and this is even worse in the night when you try to take nap and you can not. This is very hard to book a ticket in Festive seasons as all crowd moves to their native place and do advance booking for that. The better way is to book a ticket in advance and plan your travel so as you can get seat easily.
To book online ticket railway has provided a portal http://www.irctc.co.in/
One can register to book e-ticket or i-ticket. But during festive season there are rare chance you got ticket either on counter or online as there is so much crowd. Option of Tatkal booking via irctc is very bad and there are no chance to get ticket booked in tatkal for online reservation. This is due to heavy internet traffic in the opening time of tatkal i.e. 8 O'clock in the morning. Site stop responding and when site respond then all the tatkal quota is booked by the counter people. So better way if you are doing tatkal booking is to book from counter in case you did not find Agents queue in front of you then you can get a ticket.
Other option is that give your tension to agents and they will manage easily as they start their queue one day before tatkal opens and always on the front seat. But the people standing in line which can not afford them hates such corruption in the railway department.
So better is this plan your travel before enough so that you can get ticket as early as possible.
As if you are ready to stand in a queue early in the morning near about 4 am then you have a little to get confirmed tatkal ticket else there are no chance. As only first 4 to 5 people in the row can manage reservation in tatkal quota because tatkal seats are filled within five to ten minutes except if your journey has less crowd.
This is my experience while booking tatkal quota at pune station.
There are some more trains available in festival season on some root and if you search seat availability in these train then there is a little more chance to get confirm ticket available on these train.