India's railway system is complicated and competitive. I spent a fair amount of time deciphering the various classes, quota codes and train schedules. Reservations start 4 months before departure and tickets are sold out super fast (especially from Nov-Mar) so reserve as far in advance as you can. Online reservation also saves you the hassle of having to battle with locals at the ticket window (madness). 1 month before departure, I was only left with sleeper class for our first overnight train and there were just 5 confirmed berths left. For 2 other overnight trains we had to catch, I couldn't get any confirmed berths and the waiting list was way too long.

A saving grace for foreigners is the Foreign Tourist Quota (FTQ). You can check availability under this quota online but you can only buy it when you are in India. On average there are 2 places per class. Can you imagine how nerve wrecking it was to monitor the status of that pathetic 2 places everyday and keeping your fingers crossed they are still available when you finally get to India? Now the tricky part is not every train station sells FTQ tickets and there is no official website listing where are the reservation counters. Sealdah train station does not have a FTQ window. Go to Fairlee Place reservation office at 17 Netaji Subhas Rd instead! Opening hours 10am-5pm (Mon-Sat), 10am-2pm (Sun, public holidays). Counter is temporarily closed during lunch hour between 1-2pm. Grab a form and number, wait for your turn and keep your fingers crossed.

If FTQ is sold out and you can't afford to wait, try transferring a few trains to get to your final destination. For this you may have to seek help from an agent who is familiar enough with train routes and schedules. If this can't work, there is one very last resort which involves some risk-taking. Agent told us we pass off as Nagaland people and we could sneak in using VIP quota. If anyone has tried this and it works, pls let me know.

Below are some links which I find useful:
1. A beginner's guide to train travel in India: Comprehensive introduction to the various classes and step by step guide on how to purchase tickets online
2. Globetrooper Todd's How to plan and book a train trip in India: Simple overview including how to check availability and steps involved to book FTQ tickets
3. Indian Railways RAC and Waitlists: Detailed explanation on RAC/WL tickets and how they work
4. Indiamike.com: If you can't find what you're looking for anywhere, post your questions on this India travel forum, some very experienced members may be able to answer your questions.