There might be billions of tricks to get upgraded to Business and First class Airlines. However, they all require more than praying and good behavior.
Hold Frequent Flyer Status with an airline
Anytime the airline has oversold their seats (especially possible between major cities – Mumbai-Delhi, New York – Boston, London-Paris are few examples where it occurs frequently. There might be a holiday season etc.
Usually, members with top tier get upgraded
Bid for Upgrade
There are many airlines that allow you to bid your price online or during the check-in. They are a fraction of the price that you would pay to get full upgrade. Many airlines have fixed cash prices to upgrade.
Most of the airlines allow you to use your miles to upgrade your seat category. It only makes to upgrade one level. It would be a very stupid use of miles for 2 level upgrades. Now it depends on the airlines’ configuration.
Some airlines have
Economy > Premium Economy > Business Class
(In this case, it doesn’t make sense to upgrade from Economy to Business. I would rather buy Premium Economy and be upgraded to business than Economy to Business).
Other airlines have
Economy- Business Class – First class configuration.
(In this scenario, the smart choice is to use Economy to Business but a very bad choice for Economy to First.)
Most airlines have Economy and Business Only
Buy Targeted Tickets
I have done this so many times where I would buy business class and would automatically be upgraded to the first as the condition of the sale. Etihad, Gulf Air, KLM and Singapore Airlines keep having those offers.
Buy Mixed Class Cabins
Get ticket of Economy for a certain sector and business class for another. Normally when such mixed cabin tickets are issued on same PNR – it creates a logistical issue for airline as the fare rules of bigger class apply.Example if you are flying Dubai – London on Business Class and London – Berlin on the economy, you technically get all the features of business class cabin and airlines might upgrade you full way. Many times I just get my flight changed and get on one which has business class option vs all economy flight. Airlines have authority to put you on another flight.