Allotment chances for everyone will be same but you can follow the below explained way to increase your allotment chances. (If you are applying for a single lot then please ignore this). If you are applying for more than 1 lot, instead of applying all the lots from a single demat account you can divide the number of lots and apply from multiple demat accounts of different users.
Example: If you are applying for 5 lots, then instead of applying all the 5 lots from your demat account - divide the lots among your family members and apply from their accounts as well. Assume that there are 3 demat accounts in your family including yours then you can apply 2 lots from your account, 2 lots from 2nd family member demat account and 1 lot from the last 3rd family member demat account. (as per this example).
**Do not apply from different accounts on your name (with same PAN) - all the applications will get rejected.