We spent a lot of time and energy trying to book vaccination slots for ourselves and eventually succeeded. Hoping we can help some others do it too, here's what worked for us -
Be willing to travel
A lot of people are limiting their searches to their localities. Distribution of slots and vaccines, as well as population densities are not same everywhere. You have greater chances of getting a slot if you search other districts closer to you as well.
Preferably, don't have a preference
If you do not have any pre-existing conditions with known complications with certain vaccines, your focus should be on getting vaccinated asap rather than getting a particular one. Waiting for any particular vaccine isn't worth it when yours (and your loved ones') lives are at risk meanwhile.
Join telegram alert groups
Visit under45.in and join all telegram groups of your city. You will get an update on the group whenever a slot opens.
Here's the catch though, don't assume that you'll get the slot if you immediately act on it. These alerts are posted a minute or so after the slot actually opens. By the time you get on the website, and even reach the booking page, chances are that it'll show you the centre fully booked when you enter the captcha.
We did this for 2 weeks and got nothing.
How to use telegram alerts
You can use the telegram groups to keep a mental note of timings/patterns when the slots drop and which pincodes have more slots than others.
For example, after 2 weeks of non-strategic search, we narrowed down our search to 3-4 pincodes. We could see that their slots were being released at around 10pm. Every pin code has multiple centres and each centre ans multiple sites (S1, S2, S3 etc).
Once you have identified those pincodes and timings, be on the website at that time and refresh every 10 seconds like crazy. In our case, once we got an alert for slots at one site in a pincode (110094), we kept refreshing it and booked two slots separately in the same pincode within 5 minutes.
Book for 1 person at a time
There is a greater chance of one person being assigned a slot at once than two or more.
Book via Co-win
You can book through Aarogya setu app as well, however there is a drop down menu on every step and you can check availability at only once centre at once. The process takes longer, hence, not recommend, specially for 18-44. Speed is the only thing that matters here.
All the best, we hope everyone gets vaccinated soon :)