Use IRCTC R-Wallet. Even though, it is not the cheapest method to book a ticket, it is the most convenient and fastest way. Remember that every second counts while booking under tatkal quota.
Copy password to clipboard or use a password manager
Copy the IRCTC eWallet password to your clipboard (by pressing Ctrl + c, CMD + c or any similar method). Or use a password manager such as Google Password Store to save your eWallet password. In this case, you don’t have to type in the password. The password is filled automatically or using a simple drop-down menu.
Open your email
The OTP is sent to mobile as well as to the email. Email has always been faster to arrive than an SMS. Some SMS may never come too. Email is not like that. It always reaches the other end. Also, OTP in email can be copied and then pasted, especially if you use a computer while booking. This method is less prone to errors. Reading OTP from SMS and typing in the keyboard may result in typos. We are human. No human is perfect.
Prepare the passengers list
Typing every passenger’s name, age, gender, berth preference, etc can waste our precious time during tatkal booking. Always, save your passengers list in your IRCTC profile. And select the passenger/s from the list during the booking process.
Use a computer
Not tablet or mobile. Only when you don’t have a desktop / PC / mac around, you may use a tablet or a mobile. Mobile should be the last option. In online, you may have noticed a lot of recommendation to use only mobile due to limited amount of internet resources required to book a ticket via mobile. On desktop, the whole site needs to be downloaded by the browser during booking. Valid argument. I was successful in using mobile to book a tatkal ticket in under 90 seconds too. However, it failed me once and then I stopped using mobile app for tatkal booking. I was using the standard procedure to book a ticket. The last step is to fill the OTP. OTP also came to me. At the time of this writing, IRCTC uses 6-digit OTP as a standard and uses 5-digit OTP too at rare occasions. I received 5-digit OTP on that fine day when I failed to book a tatkal ticket (and had to use costlier ticket and a longer route to reach the destination at a much later time). You may wonder what’s wrong with 5-digit OTP and it is actually shorter and quicker to type than a 6-digit OTP. The problem with 5-digit OTP is that the mobile app had a bug. The bug allowed only 6-digit OTP. When I entered 5-digit OTP, the “submit” button didn’t show up. I am not sure if the bug is fixed. However, I am sure all mobile apps are going to have a bug at some point. You don’t want to get embarrassed with that bug when you book a tatkal. On the other hand, desktop version is less prone to bugs, as it is updated less frequently than mobile app. A mobile app has to go through multiple layers of testing. Desktop version doesn’t have such large variations to test drive. Most of the bugs in desktop are caught during the development. Live (desktop) version always works as expected.
When to use mobile app
Only when you don’t have a computer around, you may use a mobile or tablet. Even when you don’t have a computer around, use the browser in your mobile. Mobile App should be the last option to book a tatkal ticket. Whether you use a browser or an app in the mobile, please make sure to use a password manager like LastPass.